Terragenesis has an article on building an underground Jedi headquarters. It would work as a Hobbit house also.
Modeling
Making A Fuel Depot
Terragenesis has a tutorial on making a nice looking fuel depot from the green floral foam.
I always knew there were wargames applications for that stuff.
Modeling Alien Plants
Terragenesis has a nice article with ideas for modeling alien plants.
Building A Magnetic Scoreboard For Bloodbowl
Boromir and Kermit have a tutorial on building a magnetic scoreboard for your Games Workshop BloodBowl games. Actually, there are a lot of sports games out there right now, and this would be adaptable to any of them.
Making Hexagonal Terrain Pieces
Small World Productions has an article on using Litko hex pieces as bases for terrain pieces. They look quite good.