Sascha Brandt and Roman Schaub have released a pretty impressive GBA game which was planed for a commercial release, but is freeware now.
It's a point-and-click adventure where you take control over a hero called Russ Kimble. Experience one of the biggest GBA-adventures ever produced. Where other classic titles feature about 100 locations, The Last Seal features more than 180 locations split up into more than 500 detailed rendered screens, with character-animations exceeding the magic 1000-frames-barrier!
Give it a go and feel free to donate them for their hard work.