a blunt is rolled with tobacco leaves. usually a cigar is split lengthwise, the contents emptied, then filled with pot and rolled back up. some cigars have a perforation below the outer layer of leaves so it's easy to break open by hand (Philly's Blunts).

Blunt Rolling: how to roll a blunt (pretty decent, not much detail.i've never seen anyone pass out trying to hit a blunt)

rasta you can read about here: Rastafari movement - Wikipedia, the free encyclopedia