Brainstorming mini-quests

[true_shinken]

My players will be in a Stargazers hideout for a while and I want ideas for miniquestes and challenges to throw at them. Just quick, fun stuff for them.
Oh, basically, the Stargazers are spellcasters specialized in evocaton.

Their characters are:

• A human Spirit Lion Totem Barbarian/Hellreaver based on Thor
• A human spy with Taint issues. Rogue/Invisible Blade
• A dragonslayer in search of redemption. Mystic Ranger/Assassin/Jade Phoenix Mage
• An honor-bound hobgoblin arcanist. Sorcerer/Fighter/Abjurant Champion
• A saint in the skin of a demon. Hellbred Tashalatoran Monk/Ardent with VoP

They are all around level 10-11

[Gamerlord]

A Stargazer who delved too deeply into the forgotten books of old arcane has gone mad, and has blockaded himself in the hideout's library. The heroes must defeat him somehow, either through simply killing him or convincing him to stand down somehow.