[custom funvehicle] Need idea\'s

[w00p]

So, because my grandmother has moved from her house into a small appartement (hip operation, house was way too big, even before the new hip) she had some stuff she\'d never need anymore.
Like her lawnmower... It was a 5HP Briggs & Stratton Quantum XTS 50.

Doing a little research about it, I realised it has quite a pwnage engine...
It didn\'t work but I took about 20 mins of free time to debug it, and got it running. Apparently, theres a throttle valve (edit: after some more research it appears to be the choke valve, part of the carb... explains alot) between the carb and the block itself. I had to keep it open while starting the engine, and let it go freely in a few seconds or the engine just puffs a bit and comes to a complete stop again.
The engine runs fine apart from the starting problems, and since nobody needs 2 lawnmowers, one has to go.
We\'re keeping the honda 5hp since its a self-propelled and the B&S... well, isn\'t.

So I have a fairly decent engine to play around with, and now, I have a challenge for you people:
Help me decide what to do with it.

Stuff I have access to: welding, drilling, etc
Stuff I don\'t have access to: TIG welding (so no aluminium frame ), funds over 200€
So keep it cost effective and do-able!

What features must it have?
-Light frame
-Not too expensive, so don\'t come around with something like a mini kitcar or something...
-1 or 2 seats
-must be manouvreable
-not to be equipped with reverse or neutral (though neutral should be quite handy...)
-it should be able to handle light offroading. (just a bit of driving on a bumpy grass field)
-more than 2 wheels, unless you add funds so I can build something with adequate materials and precision.



Suggestions, concept drawings, all are welcome!
Lets see how good you all are as designers.