I never know what to do here. Lead or check?

Full Tilt No-Limit Hold'em, $2 BB (9 handed) Full Tilt Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

saw flop|saw showdown

MP3 ($269.15)
CO ($255.95)
Button ($195)
SB ($211)
BB ($125)
UTG ($133.20)
UTG+1 ($200)
MP1 ($202.80)
Hero ($289.95)

Preflop: Hero is MP2 with 2, 2.
UTG calls $2, 1 fold, Hero calls $2, 2 folds, Button raises to $11, 2 folds, UTG calls $9, Hero calls $9.

Flop: ($36) 2, 2, 9 (4 players)
UTG checks, Hero checks, Button bets $20, UTG folds, Hero calls $20.

Turn: ($76) 8 (3 players)
Hero checks, Button bets $34, Hero raises to $168, Button calls $130 (All-In).

River: ($404) 5 (3 players, 1 all-in)

Final Pot: $408

Results in white below:
UTG+1 doesn't show.
Hero has 2h 2c (four of a kind, twos).
Button has Ah Ac (two pair, aces and twos).
Outcome: Hero wins $408.