Let me say up front that I do this whole “check and figure it out” thing entirely too often against good players, and I have to stop. That said, in this case something about his turn bet led me to conclude that I ought to call the river.

Full Tilt No-Limit Hold’em, $10.00 BB (6 handed) – Full-Tilt Converter Tool from FlopTurnRiver.com

BB ($2000.30)
Hero (UTG) ($2000)
MP ($1543.50)
CO ($1734.80)
Button ($2358.50)
SB ($2077.70)

Preflop: Hero is UTG with 5, A
Hero bets $33, 2 folds, Button raises to $106, 2 folds, Hero raises to $266, Button calls $160

Flop: ($556) 6, A, Q (2 players)
Hero checks, Button checks

Turn: ($556) 2 (2 players)
Hero checks, Button bets $290, Hero calls $290

River: ($1136) 4 (2 players)
Hero checks, Button bets $1801 (All-In), Hero calls $1442.50 (All-In)

Total pot: $4021 | Rake: $3

Results:
Button had 8, 9 (high card, Ace).
Hero had 5, A (one pair, Aces).
Outcome: Hero won $4018

Let me kick this one to you, dear readers. Can you figure out what it is about the sizing of his turn bet that led me to call his overbet shove on the river?