It's pretty simple.
Windows Media Center has 'extras', and a number of these extras are nothing but web sites, rendered on the host computer, and forwarded to the xbox 360 through some modified version of RDP.
Using a modified hosts file on the host, it's simple to get these sites to display whatever I want, HTML wise, but seeing as how it's running in IE, ActiveX controls work too. At first, I wrote a simple one in VB6 to use 'shell' to execute a program, only to find out that the window is immediately taken off of my screen. Rather it's closed or just minimized, I still don't know. But, this reminded me of a program called Tegosoft TegoWeb, which 'stuck' the window into the web browser. By using this on an NES emulator, I've been able to get the emulator to stay foregrounded, and be for the most part playable.
I'm using LightHTTPD for the web serving, modifying HOSTS to point the domain I want at localhost, Tegosoft TegoWeb for the ActiveX, and tweaking permissions on a folder, to allow TegoWeb to work(it was originally targeted at Windows 95/98, I believe.) RockNES X is the NES Emulator I used.
Inside this file, the 'Instructions for Installation' should walk you through the process pretty easially.
This was written on Windows 7, but I've done it on Vista too, but that was about 6 months or so ago, so I can't recall all I was doing. XP Compatability is unknown.
It should work on Windows Vista Home premium/Ultimate, Windows 7 Home premium/Ultimate, and possibly XP MCE.
I'll try to help anyone with any questions on this.
The pre-configured files I made, with installation instructions. Assumes that your 360 is already set up as a Media Center Extender.
Edit: Added a program I forgot to list.
Edited by netham45, 14 September 2009 - 06:15 AM.