When House is playing on-line poker, he asks Taub if he should call or raise with a "double gutshot straight draw." When the poker screen is shown, House is holding 8-9, and the board is 10-A-2-7. House therefore has an open-ended straight draw (four consecutive cards, 7-8-9-10) needing either a 6 or a Jack to make the straight. A "double gut-shot straight draw" would have the same number of outs, but the gaps in the straight would be inside, rather than on the ends (e.g., holding Jack-9 against a board of 7-10-King, where an 8 or a Queen completes the straight). The odds of making the straight are the same for open-ended and for double gutshot, as for each there are exactly 8 cards that will make the straight (e.g., four 8s, four Queens), but House's identification of the hand he is holding is incorrect.
It makes no sense for Taub to involve House in his alibi for cheating on his wife. It was certain to make House curious inevitably resulting in House meddling and messing things up for Taub, who is too cynical and intelligent not to anticipate that. The logical thing would have been for Taub to keep House as far away from his infidelity and entire private life.