This auction was occurred on a randomly dealt hand during an advanced bridge class. I have seen the first four bids of the same suit by each player, but never before five consequetive bids!
With no-one vulnerable, South's 1C opening was natural; West's 2C overcall, a Michaels Cue-bid, indicating at least 5-5 in the two major suits. North's 3C was natural and weak, and East's 4C showed similar length in both majors (it was four of both suits here, but it could have been a good quality three of each), and an active desire to play at the 4-level. South's 5C indicated what was likely to be a 6-card suit.
When everyone had recovered from the shock, West thought long and hard before bidding 5S. Here was the full deal:
If East-West had known that 5S would make - which it does - I am sure that West could have mustered a sacrifice in 6C but, having pushed the opponents to the 5-level, it was probably wise to leave them to play there. After all, no one really knows who will make what...