Well here is a few of what I have.... (note these were all free when I downloaded, hopefully they still are!!!)
This one was free (I never pay for apps, just wait for them to go free) but looks like there is a 'lite' free version. But if you started gaming on one of the first 1st person 3d shooters, you'll recall Wolfenstein 3d!!! Yep, you can play it on your iPad for nostagics sake!
There is an interesting side scroller called "Papercut" for the iphone that my kids enjoy, pretty sure its free.
I recently found a free utility called "USB Flash Drive" that let you transfer between devices running it on wifi or bluetooth so kinda handy if you have multiple devices expecially w/o data plans!!
"GoSkyWatch" a planetarium for iPad is pretty cool! you can take your device outside and it will align to the stars in your area (somewhat close) and then you basically hold it up like your looking through it and the center marker will show you what your looking at! Great for identification of the constellations and such!! Not sure why my kids think they can point at any random star and I should know its name!?!
"JetPack Joyride" another decent side scroller. Kids enjoy it so must not be too bad! You can buy coins but I never have. Nice graphics and lots of ways to change up the gameplay. Your basically in some research facility flying around on a jetpack collecting coins and knocking over scientists while giant lasers and high voltage couplers try to fry you. You can get numerous power ups for you jetpack.
"Convert Units Free HD" Looks like a calculator to input values. You have a dial on the left for your starting unit and a dial on the right for the converted unit. In the center you get a drop down of types of units (angle, currency, energy, length, temp, vol, time....) over all a very handy tool! I've used volume ALOT, never could convert oz to liters or quarts to cups!!
And one last one. If you want a great Christian radio station online, try "RadioU"! Great listener supported commercial free station that plays all the current heavy metal, punk, rock, hiphop..... Even has an alarm clock feature to come on at a set time. The morning show in particular is geek friendly and often has video game reviews / trials and they often talk about the latest geek news(E3 announcements, new games...)
Anyway, thats some of what I've got on mine!