One is entertained by member running around rubbing glasses (8)

'rubbing glasses' is the definition.
(glass instrument rubbed to make a sound)

'one is entertained by member running around' is the wordplay.
I cannot quite see how this works, but
'one' could be 'i' (Roman numeral) and 'i' is located in the answer.
'member' could be 'arm' (member can mean a limb) and 'arm' is present in the answer.
'running' could be 'on' (eg when a machine is running it is on) and 'on' is found in the answer.
'around' could be 'ca' (circa) and 'ca' is found in the answer.
This accounts for all the letters.
This explanation may well be incorrect...