not invite to play really, as much as focus on specifically one server each night. instead of having different ppl try to get the same ppl to go to their server, which is usually low in population so ppl don't want to play there, have all the regs that are willing and admin and whatnot go to ONE server. ppl are more willing to go to server's that are fuller, even if they don't normally play there. changing the server each night gives "advertising" to each one allowing ppl to get to know the different servers and play some new ones. then, they might invite ppl. it's basically just a small advertising schema aimed particularly at an individual server each night.