[anonymoushn]

On the iPad in particular, you might try https://itunes.apple.com/us/app/10000000/id544385071?mt=8. It's a mission-based real-time puzzle game. The gameplay is pretty enjoyable and you can clear stuff while dramatically under-leveled so it doesn't become too easy when you get good at it.

You could also pick up a CAVE game, but it would be by no means indie...

On the PC front I am familiar with more options, but it really depends on what you like. I play mostly shmups, puzzle games, and platformers, which happen to be really easy genres to make indie games in. Over the last few years I've enjoyed Jamestown, Thomas Was Alone, Electronic Super Joy, Antichamber, Super Hexagon, and a lot of games that are distributed for free in places like http://www21.atwiki.jp/iwannabethewiki/pages/283.html

[archagon]

For anyone into CAVE-like games, please give Danmaku Unlimited 2 a try. One of the best shmups on the platform, beautiful, made by one dude.