Flash Game - Fantastic Contraptions

Good Game...

 

http://www.fantasticcontraption.com/

 

If you have a Nintendo DS you can get a very similar game called
Mechanic Master:
http://www.play.com/Games/DS/4-/5600175/Mechanic-Master/Product.html

That's good fun.

And if you don't mind running the DosBox emulator you can still
download The Incredible Machine from Abandonia:
http://www.abandonia.com/en/games/25/Incredible+Machine,+The.html

and sequel:
http://www.abandonia.com/en/games/395/Incredible+Machine+2%2C+The.html

For free!