Does it have a horizontal shaft or a vertical shaft? If horizontal and you’re interested in generators, you could hook the engine up to a suitable generator head with a belt. 6.5 HP would be good for somewhere in the neighborhood of up to 2,500 to 3,000 watts. Disregard this, if the engine has a vertical shaft.
If it has a vertical shaft, I suppose you could drive a generator/alternator head with it and some kind of horizontal belt setup. If with a vehicle alternator, it might be good for a battery and inverter.
If you have electric car (Volt) you can use it as auxiliary power supply and take a long vacation out west.
I worked on hundreds of mowers over the years as a hobby. since it is vertical shaft you can try the following: pressure washer, log splitter, or generator. If you look on craigslist for people that have those items listed you will see a lot that say the engine on theirs does not work, needs a tune up, etc. You should be able to swap the engines pretty easily as long as the shaft diameter is the same. I would not throw it away or swap it if you have the room to store it. If you store it, make sure you drain the oil or make sure it is sitting level or you will find the oil will seep into the cylinder.
Drain the tank, run till the carb is dry, box it up.
Watch for a mower that has a broke engine (craigslist, neighbors, etc.), and you will have a backup, or a salable mower.
Build a bridge out of it!!