A Marble Tower I made a while back.Won't do it again.It has 13 different species of wood and took me about 2 months to complete.It did win me a 100 dollar gift cert. to Woodcraft in one of the shows they have.
You can get the plans here.http://www.woodcraftplans.com/fsmt.htm Good luck.Hehe.It's not that bad just very time consuming.Lots of small pieces and the marble release mechanism has to be pretty exact or it won't work right.