SL4ASL4A is an open source software by Google for android mobile phones that allows you to run various interpreters like Python, Perl and much more on your mobile phone.
It's very interesting because with it (and a little programming skill) you can automate your phone and do a lot of very cool things with no need for a computer: you can write your program directly on the mobile.
Unfortunately, I found a couple of issues and I tried to fix them. If you (like me) don't want to wait for the official release, the following apk includes my patches for issues 543 and 544.
Download patched SL4A
The apk is signed with my key, so if you already have installed SL4A you will probably need to remove it before installing this patched version.
Also I think SL4A still lacks a feature: scheduling tasks periodically or at a given time. That's why I developed a simple crontab-like task scheduler (which I called ChronoTrigger -- I loved that game, hope nobody complains about that) that lets you run scripts periodically, even when the mobile is in sleep mode.
Download ChronoTrigger for SL4A
ChronoTrigger is open source: the source is hosted inside my clone of SL4A in Google Code and can be found here.
Hope you enjoy!