Sorry for my ignorance,but I have just recently realized the Flash player can be used to play Flash games.
I have downloaded several games,they don't run too fast,but for fun it's ok

If you wanna get them from websites start the choosen game online.In firefox go to Tools>Page Details (or something similar,I am not sure since my default language setting is not English...) ,then choose "Media".Locate the SWF file and "Save as".
In Bon Echo I am not sure where it is (yet),I did it on my other computer and have transfered the files onto the Elonex OneT.
I hope someone will have some nice time,since thousand of flash games are available online,you need just to find out which ones are the most suitable.