1. A mini-van; usually as a means of conveyance for middle- or high-school aged blonde females to and from soccer practice, junior proms, etc. Origin: Neal Stephenson's novel Snowcrash- perhaps a pun on bento-box (a Japanese lunch box pre-packed with nutritious goodies).
2. Any vehicle driven by a soccermom.
"This huge bimbo-box cut in front of my ride and I couldn't see anything."
"Look out! Sally's drivin' her mom's bimbo-box."
"The enviornment can't afford any more freakin' bimbo-boxes."