Thank you Fnord! The all-in river "bluff" worked very well for me last night, I got at least two really terrible calls.

PokerStars No-Limit Hold'em, $0.50 BB (2 handed) FTR converter on zerodivide.cx

BB ($28.50)
Hero ($57.95)

Preflop: Hero is Button with A, 5. Hero posts a blind of $0.50.
BB calls $0.25, Hero (poster) checks.

Flop: ($1) 9, 8, 4 (2 players)
BB bets $1, Hero calls $1.

Turn: ($5) 6 (2 players)
BB bets $2, Hero calls $2.

River: ($15) K (2 players)
BB checks, Hero bets $25, BB calls $25 (All-In).

Final Pot: $57