Nickspoon released a Flash Player for the GP2x.

This program will play flash movies, and to a certain extent flash games. The mouse movement is a little dodgy at the moment, and there’s no keyboard or sound support. To run, simply create a script that includes the line: ./flashplay and run it from the same directory as flashplay.

http://archive.gp2x.de/cgi-bin/cfiles.cgi?0,0,0,0,8,1083