Party now and then? Given invite, go (7)
I believe the answer is:
attempt
'go' is the definition.
(thesaurus)
'party now and then? given invite' is the wordplay.
'now and then?' indicates alternate letters (I've seen 'now and then' mean this (letters taken on a regular basis, now and then)).
'given' means one lot of letters go next to another.
'invite' becomes 'tempt' (synonyms).
The alternating letters of 'party' are 'at'.
'at'+'tempt'='ATTEMPT'
(Other definitions for attempt that I've seen before include "Try to climb (a peak)" , "Have a crack" , "Stab" , "Embark on, try" , "Effort; go" .)