Guild Wars 2

I remember DAOC had a UI mod that allowed this. It was really nice because you could be semi AFK on along raid and browsing the internet or watching a video during low action times.

I noticed that I switch to windowed to watch for que pop so I can browse the web or watch some Star Craft or something. If the UI had that function built in, it would be handy.

overwolf might do it for you. goggle it