How about something else entirely? A silly Borg song..."We are the Borg" would actually fit well to replace YMCA....

It scans, but how would it fit with the rest of the song? I like to stay as close to the original song as possible, in rhyme, metre, and theme. It's great when some of the original lines fit with the altered version, like my "Doctor Bones McCoy" filk to the tune of "Good King Wenceslaus":
Doctor Bones McCoy looked out
On the feast of Stephen,
Where the food lay 'round about,
Deep and crisp and even.