Chainwriting, a CUSFS hobby, is the process of group-writing a short story. In its simplest form, one person writes a 250-word opening to a story, then passes it on to someone else, who adds another 250 words - and so on. Other, more experimental variations on chainwriting also take place now and again - see the FAQ for more detail.
Most chains have in the region of 10 people in, so a decent length story develops which can be anything from an internally consistent and enjoyable work of fiction to a bizarre hotchpotch of different writing styles. All chains get published in TTBA when they're done.
Below are some individual chainwritings, for ease of reading outside of TTBA. In particular, the descriptions may indicate how CUSFS actually remembers each story...
Signups are usually circulated for a week or two at the start of the university Michaelmas and Lent terms. Often another chainwriting session takes place at some indeterminate time over the summer. Any signups will be advertised on the soc-cusfs-interested mailing list and the CUSFS Facebook group.
Once signups are being advertised, just email or otherwise contact whoever is running chainwriting (usually the TTBA Editor) to register your interest. You should let them know how many chains you're interested in writing for, whether you have any preference over position in the chain and particularly whether you'd be willing to be the first or last writer on a chain. It is also helpful to mention if you're interested in any experimental chains that have been advertised.
Experimental chains are chainwriting done in a more unusual way. They usually take place in the Lent term, by which time everyone thinks things have settled down and are going to be sensible this time. They are wrong. Examples of past experimental chains involve Backwards Chainwriting (first person writes the last installment of story, second person writes the penultimate section and so on), Markov Chainwriting (every person only sees the immediately preceding section of the story) and Nonlinear Chainwriting (any writer may insert sentences of the story between any others). Sometimes these work extremely well, sometimes they do not, but they are often very fun.
Yes, a few people take part anonymously every time. You just need to make sure whoever's running chainwriting knows - this has to be said every time you sign up, as different people may run chainwriting each term.
Anyone can take part in chainwriting regardless of CUSFS membership or student status. If you're aware of signups going on, you're more than welcome to sign up! Signups are mainly publicised on the CUSFS mailing lists and Facebook group, so you're more likely to hear about them if you're on one of those.
You can sign up to be on as many different chains as you like, although you may only write one section for each chain.