Villain hasn't done anything too eyebrow-raising but he's very loose preflop (45/25-ish) and has very high river aggression. I suspect him of being the type who hangs around in pots until other people give up, but I have no hard evidence (i.e. no specific prior hands where he showed down crap).

Full Tilt No-Limit Hold'em, $0.50 BB (6 handed) Full-Tilt Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

CO ($50)
Button ($94.20)
Hero ($53.10)
BB ($100.75)
UTG ($75.35)
MP ($85.80)

Preflop: Hero is SB with .
1 fold, MP calls $0.50, 1 fold, Button raises to $2.25, Hero calls $2, 1 fold, MP calls $1.75.

Flop: ($7.25) :Ad: (3 players)
Hero checks, MP checks, Button checks.

Turn: ($7.25) :Ah: (3 players)
Hero checks, MP checks, Button checks.

River: ($7.25) (3 players)
Hero checks, MP bets $5.5, Button folds, Hero calls $5.50.

Final Pot: $18.25