I was thinking almost exactly like you guys. I figured he threw out a blocking bet with some sort of middle pair, A9, etc. Since a raise would basically put him all-in, I decided to just shove. And...
Party Poker No-Limit Hold'em, $ BB (6 max, 5 handed)
converter
Hero ($688.95)
Button ($2206.9)
SB ($542)
BB ($757.6)
UTG ($634.1)
Preflop: Hero is MP with 4[img]/images/graemlins/spade.gif[/img], 6[img]/images/graemlins/spade.gif[/img]. SB posts a blind of $3.
<font color="#666666">
1 fold</font>, <font color="#CC3333">Hero raises to $21</font>, <font color="#666666">
1 fold</font>, SB (poster) calls $18, <font color="#666666">
1 fold</font>.
Flop: ($48) 9[img]/images/graemlins/spade.gif[/img], 4[img]/images/graemlins/heart.gif[/img], 4[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
SB checks, <font color="#CC3333">Hero bets $35</font>, SB calls $35.
Turn: ($118) 8[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
SB checks, <font color="#CC3333">Hero bets $70</font>, SB calls $70.
River: ($258) 2[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">SB bets $100</font>, Hero calls $562.95 (All-In), SB calls $316 (All-In).
Final Pot: $1236.95
Results in white below: <font color="#FFFFFF">
SB has 2c 2h (full house, twos full of fours).
Hero has 4s 6s (three of a kind, fours).
Outcome: SB wins $1090. Hero wins $146.95. </font>