i have to make a post about this fantastic suite of tiny, portable puzzle games, just in case anybody has not heard about it yet.
http://www.chiark.greenend.org.uk/~sgtatham/puzzles/
27 free games
all single EXEs
entire suite is just 4mb
well conceived, well implemented, and tremendously entertaining
and best of all, multi-platform
check it out if you have a few hours to spare