Reply to VJing/Visualizers for a party

Hello all! This is my first post but i've been following the blog for a while now, love everything you all do!

The question i pose is similar to VJ articles that have been on DJranking s, but none of those articles quite solve my problem.
I am Djing for our school's student sixth form after-party, where we get a big marquee in a field with visuals and a big speaker system and have a big party. I want to incorporate some kind of visual projection behind the DJ booth, that would be able to run un-touched for most of the time, but be triggered into changing patterns or speeding up at particular moments in songs, either by keyboard shortcut or a midi controller. I would also like to occasionally play video that would not need to be beat synced (ie. Lyric/Music videos for certain songs), and thus would want the video to mix in from the visuals (although this isn't necessary). Ideally all this would run from a secondary computer from an AUX in off the mixer. Does anyone know of software capable of doing all this (baring in mind i currently have no VJ content of my own).

I'd appreciate any help what-so-ever.

Thanks,

Hugh