I've bought a storage unit, and truly have no idea what these Mega Bloks are a part of.
There are two blue domes, two green domes, and a bunch of what looks like tracks/road pieces.
Those track pieces appear to resemble in shape (if not in color) the track pieces in set 9801 Build & Race Speedway:
No idea about the "domes". Could they be lids to containers?
Brand: MEGA BLOKS.
Set Theme: Planetoids.
Set Name: LX-009 City.
BIG THANKS to Gnovice for the positive I.D. on the track piece, which proved it was at least from the MEGA BLOKS line, but just in a different color.