I'm fascinated that Card Caper is being marketed in its current form. Rather than convert it to use a proprietary deck, University Games went with a standard deck and a somewhat superfluous game board. Which means that anyone who knows how it plays could easily do so without purchasing a copy. Of course, the same is true of many games like Uno and Pictionary, but their sales don't seem to have suffered— so what do I know?
Card Caper is a logic game in which each player tries to deduce the secret card of the others. The deck is dealt out among all players. The first card each player receives becomes their secret card while the rest comprises their hand. Players record their cards on a Clue-like notesheet and play begins.
Each player in turn rolls a die and moves a single shared pawn in either diretion around a circular track. The pawn's resting space dictates the player's action for that turn— either giving away information about their own secret card or guessing at the identity of an opponent's card.
Information comes in four flavors. Landing on DIFFERENT SUIT requires a player to play a card from his hand which is not the same suit as his secret card. LOWER VALUE or HIGHER VALUE forces the play of a card which is lower or higher than the secret card, while DIFFERENT VALUE just requires a card which doesn't match the secret card's value. New information must be provided if possible— you can't just keep playing diamonds for the different suit if you've got other suits available. Part of the strategy lies in choosing which cards to play in order to provide the least information to opponents. Often the best choice is fairly obvious, however, so it sounds more strategic than it really is.
The other spaces let a player guess at an opponent's card, and in some cases first ask them for a specific kind of information. If a player guesses incorrectly, whoever holds the guessed card plays it to the table. If the guess is correct, the guesser earns one point for each card remaining in the guessed player's hand. That player isn't out, though— there are still other cards to be guessed, and the cards in his hand are kept private until revealed in the course of normal gameplay.
The game ends when only one player's secret card remains unknown. That player earns five bonus points, and the high scorer wins.
Card Caper is not a game for serious players. There really isn't a lot of scope for strategic play, and guesswork can pay off as much as deductive reasoning. A lucky guess or roll early in the game can be hard to overcome, since players will lose cards as the game progresses and correct guesses become progressively less valuable. Rewarding earlier (and thus ostensibly shrewder) guesses makes sense, but ignores an important element of game design. Generally you want scoring to increase towards the end of a game to make for exciting finishes where everyone has a chance at winning. Card Caper is a game of attrition where you see your chance of victory slipping away with every card opponents play.
Sleuth and Code 777 (now out of print) are superior logic games with greater appeal— the former is more challenging than Card Caper, and the latter is simply more fun.
That said, Card Caper is not without merit— especially to a younger or family crowd. Kids and adults can play this game on fairly even footing, and it's simple enough for kids to enjoy without all the die-rolling and pawn-moving of Clue.
Card Caper is neither awful nor particularly good. It might have been more effective with different theming instead of a regular deck, but using that deck probably makes it more approachable to your Rummy-playing family members. If that's worth something to you, Card Caper might be a good buy. For the childless among us whose families don't play Rummy, there's little here to recommend.