Probably the best by far. Maybe I'm being a little biased and a little too generous with my rating but this would definitely have to be one of the funniest, most eventful half our of television I have seen. Other sitcoms should watch TBBT and take notes, seriously, this is what a good sitcom should be.
Not only was it absolutely hilarious with Leonard's mother and Sheldon interacting but it was also surprisingly eventful. We haven't got a Penny/Leonard hinting since the beginning of the season. Mostly we've been getting Sheldon-based episodes which isn't necassarily a bad thing when it comes to comedy but it looks like this show mastered both the continuity and comedy tonight.
Penny & Leonard almost having sex was big, not to mention the events leading up to this occurence was hysterical. Knowing this show, the almost hook up wont change much, but it was still great to see. Perfect TBBT tonight, best by far.