Reply to Max/MSP and Max for Live - what are they?

Yo,

I'm looking into the whole monome and more open source approach to performance in Ableton (just for funsies, I'm not techy enough to achieve anything though!) and I can't find any conclusive answer in terms that I understand to my question:

What is Max/MSP and Max for Live? (obviously, i understand the second is an Ableton resource for the first..)

If anyone would be so kind to impart some of their wisdom on the topic, it'd be gratefully appreciated