Bit random this one but I cut a few oak purlins down a while ago.
Had em lying around the place for ages then drilled a hole down the centre from the top to meet up with a hole I drilled from a few inches up from the bottom in from one side.
Kind of a wooden rocket stove.
It hardly throws any heat out (I can pick it it while its burning and move it to another spot) but its pretty good with the Kelly Kettle and serves as a talking point.
One thing to note, the one inch drill bit wasn't really enough, would be better to be a two inch hole so I could drop fuel down it till the inside of the oak catches.
Once its got upto that size its dead easy to put out and re light though.