A train wreck (and embarassment) of a board:
I thought 4♦ showed a maximum original pass with slam interest, holding something like a flat hand with scattered AKK or AAK and after some cue bidding ended up in 6♦. When dummy came down I saw I needed the hand of God to bring it in, who duly obliged. Spades 3-3 with the queen onside and the club ace onside means it is cold. I apologised to the opponents for this hideous example of bridge which gave us a completely undeserved top. Afterwards my partner said she was inviting game in diamonds, not suggesting slam interest.
There was this one we missed (my fault):
My mind went blank after partner bid 2NT and I struggled to come up with a way of setting hearts as trumps and starting slam investigation. I didn't trust partner not to pass a 3♥ bid, 4NT is crap with no minor controls, and 3♠ will be taken as natural. It was a choice between 4 and 6♥ and I took the conservative option. It is there as it needs one of the ♦K or ♣A onside on a non diamond lead. Better than it should have been, the slam was only bid once (you can sometimes get away with a lot in a mixed and largely mediocre/poor field). We agreed after that after a NT rebid a club response is Checkback enquiring about the majors.
Finally there was this one where I did my best but partner wasn't on the same wavelength:
Maybe I should have bid Blackwood at my second turn and trusted partner to appreciate diamonds had been agreed, but I thought cue bidding the opps suit followed by jump raising in diamonds beyond 3NT must show a strong hand looking for slam. This was not punished properly either as +170 was worth 50% thanks to one other failing to get past 3♦ and two others going off in 4♠.
Playing in a part score with a combined 28 HCP and a good trump fit, missing a 70+% slam and bidding a <10% slam is pretty poor so partner and I have some (a lot of) work to do with our bidding.