I wonder if it is easy to build a unicycle from an old two wheel bike.
What you need to buy and stuff like that.
Rusty
Hmm…sounds like a fun project, but it might be to much work for what you’ll get out of it. You could use the fork and a uni hub, but it might not work. Believe me, I tried making one using an old tricycle tire, but it didn’t work at all. Much easier to buy a beginner unicycle.
If I had a spare bike lying around I’d think about making an eccentric bike, with the hubs off-centre in the wheels.
That would be an effective way to get stared at cycling across campus… 
Or of course you could follow UniBiker’s lead, and take the front wheel off…?
Phil
Re: Building a unicycle
I have seen some unicycles that were made from old bikes.
From the front fork you can make a standard style unicycle. Depending on the design of the fork, one option is to flatten the ends so they are like the Miyata frame
<http://www.unicycle.com/shopping/shopexd.asp?id=197>
Then use Miyata bearing holders
<http://www.unicycle.com/shopping/shopexd.asp?id=143>
This is probably one of the easier designs to use when converting a bike fork into a unicycle. It avoids the need to weld bearing holders on and is probably the most simple design. Note how the ends of the Miyata frames are flattend and then bolts are used to secure the frame to the bearing holder.
The other option is to weld main cap style bearing holders on the end of the fork.
<http://www.unicycle.com/Shopping/shopexd.asp?id=206>
The rear section of a bike can be turned into a giraffe of sorts. But that will be a lot of work. I can’t help you there. Maybe someone has a good picture of a giraffe made from a bike. There are certainly lots of options to get creative in making a giraffe like that.
Couldn’t you just saw off the down tube in front of the bottom bracket and the top tube in front of the seat tube and then reblace the back wheel with a giraffe wheel? It would probably be a chalenge to ride though.
-Isaac