I don't care if you need to go diving between couch cushions scrounging for change to be able to afford to do it, but if you own an iOS device, you need to download Dead Space [99¢ / HD] while it's on sale for 99¢. Dead Space for iOS is a phenomenal taste of the Dead Space universe if you've yet to dabble in the "full" console titles, and at 99¢, flat out cannot be beat. We thought it was great in our review, and a recent update addressed our main gripe with the game's controls.
There are a ton of other games on sale for the holiday weekend. We'll go through and list out the good ones soon, but in the meantime do not miss Dead Space. If you want to trudge through all the games on sale yourself, head on over to AppShopper to find a listing of absolutely every game that has had its price drop. Do this after you've downloaded Dead Space.