Play Simples Minecraft Skyblock with a colleague?

Is there an easy way to play a very simple version of Skyblock with a friend? Without farm islands and shops, just Coop with Challenges + rewards?

Am very inexperienced in the field and find nothing suitable in the Web.

Of course there are possibilities. On matching servers, there's not much schnick schnack. I think on Mybukkit.de you can play Skyblock check it out if not google times Skyblock server