What would you bid over Gerber?

I played online bridge tonight with Notzia. We usually both show up and one of us plays with Kate and the other plays online poker instead. She wasn't there tonight, so we partnered. The mini-tournament we played in had 12 deals. They saved the best for last -- board #12 was a doozy.

You are first to bid, Your side is not vulnerable, the opponents are. You hold: ♠A K 7 5 ♥A K 8 ♦J 8 7 5 ♣10 8.

You bid 1NT, partner bids 2♦, a transfer to hearts. You dutifully bid 2♥, and partner gives you 3NT, a choice between 3NT and 4♥.

Out of the clear blue, your right-hand opponent bids 4♣ vulnerable !! Has he lost his mind? Did he escape from the mental ward and take over somebody's computer? Is he a serious meth addict? He's likely from an alien planet, and they let him come down to earth now and then to play online bridge, before whisking him home -- yes, that's it.

Actually, I didn't hold the hand I gave you. I was the psycho who bid 4♣. The guy who held it doubled. He was right about one thing. 4♥ doesn't make (with a diamond lead).

                     ♠ Q 9 6 5 2
                     ♥ 10 5 3 2
                     ♦ K 6 3 2
                     ♣ ---
♠ A K 7 4                          ♠ J 10 8
♥ A K 8                            ♥ Q 9 7 6 4
♦ J 8 7 5                          ♦ Q 9 4
♣ 10 8                             ♣ K 9
                    ♠ 3
                    ♥ J
                    ♦ A 10
                    ♣ A Q J 7 6 5 4 3 2

(If you are a poker player, notice that South holds a straight flush!)

I easily made 4♣ doubled for a score of plus 710 and a pickup of 7.58 IMPs. The results were all over the place. One pair was doubled in 3♣ and made six for a score of 1270. Made six? You can see how they did so and all the other results by clicking here.