Challenges for Game Designers is an app based on the book of the same name by Ian Schreiber and Brenda Brathwaite. The app contains a "deck" of 300 cards, one card per challenge in the book, plus a few extra challenges not in the book. If you have a few minutes and want to try a random challenge, just let it deal you a card, and go from there.

Also included is a game jam constraint generator disguised as a slot machine. Pull the handle and it'll generate a random set of constraints (such as a given theme, core mechanic, or game genre). Take a weekend to make a game that fits... or if you don't like it, just spin again.

Lastly, it also contains a game design game, for groups of game designers. Like the slot machine, it generates a set of random constraints, but this time it also has a timer that counts down (you can set it from 1 to 10 minutes). Roll the dice, then everyone present has to come up with a pitch for a game, before the timer runs out. Then everyone presents their game concept to the group and can vote on the best one. Then roll again.

All three features are included in the app. No in-app purchases or upgrades required - you get everything for the price of the app.