Odd: KLF & Tammy Wynette The maverick Situationist British music act teamed up with the American country music icon for Justified and Ancient. The result is a bizarre mixture of acid house and C&W - and check out the video for Wynette's obvious discomfort in having agreed to take part.
Awful: Ozzy Osbourne & Miss Piggy Yes, it's meant to be a tongue in cheek version of Steppenwolf's Born to be Wild, but someone forgot to tell Ozzy (or maybe they did and he forgot to remember?), who gives the song heavy metal welly instead of humour.
Charming: David Bowie & Bing Crosby This one always crops up on these lists, and for good reason - it's seriously weird and engaging. The interconnected songs of Little Drummer Boy and Peace on Earth were delivered after a brief rehearsal. Bowie's reason for appearing on Crosby's 1977 TV special, Merrie Olde Christmas? "I knew my mother liked him…"
Karaoke: Happy Mondays & Karl Denver Take a 1960s yodelling Scottish pop star and a drug-happy Manchester band, put them together on the band's Lazyitis, sit back and laugh. Repeat.
Good: Kanye West & Bon Iver In which hip-hop's most adventurous/contentious (delete where applicable) practitioner cosies up with indie folkster Justin Vernon on Lost in the World (from 2010's My Beautiful Dark Twisted Fantasy). Subtle - it works!