I've been pretty tempted to create a lot of small mobile apps that'll create consolidated revenue.
The thing about mobile apps is that you're revenue from a single app will eventually diminish over time, unless you have a killer legacy app.
I'm thinking of a bunch of different ideas which you can use to painlessly create Apps that'll make cash:
1. Simple calculators ( mortgage calculator, tax calculator, country specific calculators )
2. Legacy games which are not copyrighted that can be re-adapted for the mobile / tablet.
I'm also pretty sure you'll get hundreds of App ideas just by looking at the questions people ask in Yahoo Answers or Quora.