Just aired earlier tonight, and introduced many a twist in the story line already. For those who didn't catch it, I'll spoiler tag my comments below, but I recommend seeing it soon. Spoiler My friends and I got to arguing over who's wedding it could possibly be from the fact that either Ted or Marshall were the best man, and Lily was part of the wedding party; and why Cindy and her roommate got invited (if she got invited)? My thought was that Barney and Robin somehow get married since those two are the only two who could possibly get married that we know of right now who are friends with all the group. This might be foreshadowed by the fact that Barney was awestruck when Robin came back into the bar all done up. Also, we came up with the 'mother' could maybe be working at the wedding, like a wedding planner of some sort if she didn't come with Cindy. We learned a couple seasons ago that she was in the Economics class that Ted accidentally started to teach and that could possibly correlate to some sort of work in the business field.