A barrelene is the biccyclic organic compound bicyclo[2.2.2]octa-2,5,7-triene.
A benzobarrelene is any hydrocarbon whose structure is that of a benzene ring fused with a double bond of barrelene.
There are several. Barrelene, Benzocyclobutene, Cubane, Cuneane, Cyclooctatetraene, Semibullvalene, and Styrene all possess that structure. This is so because C8H8 has a lot of different ways to combine. Further info: http://en.wikipedia.org/wiki/C8H8