There are loads of card games available for Palm, but most follow a similar pattern, and are often either a variation on a solitaire game or a matching pairs puzzle.
Grouper is a little more unique and its gameplay reminds me of those logical puzzles you used to get given in traditional IQ tests. The aim of the game is to make as many groups as you can from the cards that have been dealt on the 'table', until there are no cards left (or no more groups can be made).
Groups are based around card color, number of spots, spot color and spot type, and you need three cards to make a group. To make a group all these four characteristics must either be all the same or all different.
It sounds complicated, but you pick it up pretty quickly and there is a Hint option that recommends a good card to start with in case you're really stuck.
Grouper proves to be a real challenge, especially when you're playing against the clock at the highest of the three difficulty levels. And however infuriating it becomes, you can't help but play on to figure out those blessed groups.
The graphics are far from exciting and the patterns are not very imaginative. That said, there are a few different color schemes you can choose from in order to vary things a little.