Check out the LCDinfo plugin for meedio, if you are running a HTPC. I have not tested this feature, but check out the official forum:
http://www.meedio.com/forum/viewtopic.php?p=109909
If you insert a <requireflag> commando in the screen file, it should turn it self on and off according too what is running. I have however not managed to use this feature, as my screens do not start when I use this flag command. It will most likely be fixed in newer versions of LCDinfo.
Forceflag has also been discussed on this forum, a must for many useful things, e.g. incoming e-mail, volume change, MBM5 alerts etc.
The meedio plugin will look something like this on your display.