As it's "just for fun" this sounds like a job for...
the Zoom H2 (recording separate front facing and rear facing stereo pairs), then play around in your DAW after.
Things to help with the playing around -
AcousModules : Surround 5.0 à 7.1 Ambisonic Studio | Zoom2Five Plug-in Best Surround Sound System, MP3 Surround Sound - Vortex Surround