Of course they are not just for UMPCs, but they are advertised as UMPC and Tablet games.
First one is HangMan. There can’t be much to explain this game, so i’ll quote directly:
This is a version of the game prepared for UMPCs and Tablet PCs where the computer thinks the word and it’s our task to guess it.
The game comes with 3 lists of words, the main list of around 1000 words, the list of Capitals of Countries and the List of Countries names. You can create your own list of words in a TXT file adding one word per row, this feature makes the games virtually new every time that you add a new list of words to be used by the program.
This game is a perfect tool to practice your handwriting with the Tablet PC recognizer. You can also use it as a learning tool to teach your kids new words making the learning process a big fun.

It’s $7.49 for now, you can buy here.
Second one is InkDoku - Tablet version of Sudoku.
Introducing InkDoku: Sudoku for the Tablet PC. This famous Japanese puzzle game comes directly to your Tablet PC. Use your stylus to handwrite your answers to an unlimited number of puzzles. If your Tablet supports the eraser mode of a stylus, simply use it like you were using a pencil!

It’s $9.95, you can buy here.