I've released a preview of ETP Studio, a new integrated development environment for TI's 68k calculators.
This IDE contains a lot of powerful and useful graphic editors (tile editor, ti-bitmap editor, sprite editor and map editor) and some wizards (they can generate some code for high-score feature in your game or some display routines with double-buffering and camera move, you just have to click "Generate" and call these functions!!).
So making a game is as easy as drawing sprites!
Of course, the IDE allows you to fully customize your program thanks to the compiler of ETP-Basic which is a new langage specially created for programing on TI, simple as TI-basic but much more powerful (near to C).
This is just a "preview" version, there still are some bugs but you can already see the features of this software and use it to make easily programs

Tigen.org site which contains the news and the link to download ETP, click on "Lien vers le téléchargement (5,81Mo)"
ETP Studio official web sites (it doesn't contain the public release (not yet))
Documentation of ETP-Basic langage