Crazy about going to Yale? One counts the hours, chirpily (6,5)
I believe the answer is:
cuckoo clock
'one counts the hours chirpily' is the definition.
(a cuckoo clock audibly counts the hours)
'crazy about going to yale?' is the wordplay.
'crazy' becomes 'cuckoo' (I've seen this before).
'about' becomes 'c' (abbreviation for 'circa').
'going to' is a charade indicator (letters next to each other).
'yale?' becomes 'lock' (Yale is a brand of lock).
'cuckoo'+'c'+'lock'='CUCKOO-CLOCK'
(Other definitions for cuckoo clock that I've seen before include "Peak of Swiss achievement (according to Harry Lime in "The Third Man")" , "Bird call timepiece" , "caller on the hour" , "Swiss striker?" , "Timepiece featuring bird" .)