Kalter Schlag
I learned this game from Reinhard Spode, Sylvia Kalisch and Lutz Franke.
Introduction
Kalter Schlag is a fourplayer game from Hamburg. It is related to Ramsch, which in turn is a variation played in informal games of Skat. Literally "Kalter Schlag" means "cold hit", but it implies an element of surprise, so a more idiomatic translation would be "bolt from the blue". This name appropriately describes the way that a game can easily be lost suddenly and unexpectedly through an error of judgement or an unfortunate distribution of cards.
Kalter Schlag is played by four people, each playing for themselves. It is a tricktaking game in which the aim is to avoid winning tricks containing highscoring cards. In each deal, the player who takes most card points in tricks loses those points, and the first player who loses a cumulative total of 2000 or more points over a number of deals is the overall loser.
The Cards
A 32 card French suited Skat pack is used. The following table shows the ranking (from high to low) and the point values of the cards.
The jacks (permanent trumps)  The four nontrump suits (clubs, spades, hearts, diamonds)  



On the cards used in Germany, the jacks are marked with a B (Bube) and the queens with a D (Dame). The total number of card points in the pack is 120.
Deal and play
The deal and play are clockwise. At the start of a session, the first dealer is chosen at random. The turn to deal passes clockwise until someone loses by accumulating 2000 or more points. If playing another game, the loser of the preceding game chooses who should deal first in the next game. The dealer deals 8 cards to each player  first a packet of 3 cards to each, then 2 to each and finally 3 more to each.
The player to dealer's left leads to the first trick. Players must follow suit if possible; if not they may play any card. For this purpose the four jacks count as a separate suit.
 If a jack was led, you must follow with a jack if you have one. If you have no jacks you may play any card of any suit.
 If a card other than a jack was led, you must if possible play a card of the same suit (but not the jack). If you have no cards of the suit led (except possibly the jack), you may play any card of any suit or any jack.
If any jacks were played the trick is won by the highest jack in it. Otherwise it is won by the highest card of the suit led. The winner of the trick leads to the next.
Each of the four players, as they play their card to the first trick, has the opportunity to double the score for the hand. The first player who wishes to double says "kontra", the next says "re", if a third player wants to double they say "bock", and if all four players wish to double the fourth says "hirsch".
Scoring
At the end of the play, if one player has taken all eight tricks, that player wins and does not score, but each of the other players has a penalty added to their score. Winning all the tricks is called a Durchmarsch. Note that it is not sufficient to take all the points  even a trick with no points taken by another player stops a Durchmarsch.
In the normal case where two or more players have taken tricks, each player adds up the values of the cards in the tricks they have taken. Whoever has the most points loses, and some penalty points (calculated as explained below) are added to the loser's total on the score sheet. The other players do not score. If there is a tie for most card points, then both of the players with most points lose the full penalty.
If two or more people take tricks, the number of penalty points given to the loser(s) is calculated as follows:
 Start with the number of card points in the loser's tricks.
 If kontra was said, double it.
 If re was said, double it again.
 If bock was said, double it again.
 If hirsch was said, double it again.
 If someone took no tricks, double it.
 If two players took no tricks, double it again.
 Round the result to the nearest 10 points (numbers ending in 5 are rounded upwards).
A player who takes no tricks is called a Jungfrau (virgin). If there are three virgins, then the fourth player has made Durchmarsch. If this happens, the durchmarsch player scores no penalty points, but the three virgins are penalised 120 points each, doubled for each player who said kontra, re, bock or hirsch, but with no further doubles for the fact that three players are Jungfrau.
Note that comparison of card points is done before rounding  for example, if the points are divided 4948167, the player with 49 points loses alone even though 49 and 48 may give the same penalty point score after rounding.
Examples of scoring
 The loser has 55 points, everyone has a trick and no one said kontra. The penalty for the loser is 60 points.
 The loser has tricks containing 66 card points. One player said kontra and one player took no tricks. The penalty for the loser is 260 points (66*2*2=264 rounded to 260).
 The loser has tricks containing 63 card points. Kontra, re and bock were said, and two players took no tricks. The penalty is 2020 points (63*8*4=2016), so the loser has lost the whole game in one deal.
 One player wins all the tricks. Kontra and re were said. The other three players each score a penalty of 480 points (120*4).
End of the game  payments
When a player's score reaches 2000 points or more, the game ends and that player has lost. This overall loser pays a stake to each of the other players who have penalty points, and a double stake to any players who scored no penalty points during the game.
A tie or a Durchmarsch can result in two or possibly even three players going over 2000 on the same deal. In that case, the player with most penalty points is the loser and has to pay each of the other players. If two or more players are tied for most penalty points, both having 2000 or more, further hands are played until there is a single loser (who might be neither of the previously tied players).
Exception. If a player manages to score penalty points in five hands, but still has less than 2000 points, the game ends and the player with five scores is the winner, collecting a double stake from each of the other players.
If playing another game, everyone starts again from zero penalty points, and the loser of the game just completed decides who will deal first in the new game. In the exceptional case where a player won by scoring five times in a game and remaining under 2000, the winner deals first in the new game.