Yeah, I’m a nice guy after all.
A couple of people pinged me after I said I wouldn’t bother going after the spammers in question, so let me clear it up here:
12 year olds.
Or, theoretically, anyone between the age of 12-15.
Normally the procedure is to bounce off an email to abuse@spammers-isp.com with some detailed information and they’ll handle the case from here. If, by the way, you haven’t tried this with spammers attacking your site, I would definitely recommend — ISP administrators tend to take them down pretty quickly. Anyway, as I was preparing the details I noticed a trend in the data — then it went “!” and I realized that the spammers were 12-15 year olds attacking on the site before they went to school, and, apparently, from their school’s computer lab.
Now, I got no love for spammers, but I’d hate to inadvertently cause some collateral damage and take their parents down with them. Typically an ISP won’t let you re-sign up for an account once they drop you — most spammers have deep connections, so they either “buy” a new address or bribe local isps, but since these are pretty young, pretty stupid people we’re dealing with her, the end result would be their parental units lacking the internet for a few days, to a few months. I know how hard it can be dealing with snot-nosed brats. 
Right now I’m mulling over if I should just ping their ISP and ask them to “pass the message along” or if I should just fire off the email myself.
In related news, the spam filter is working well — I’ve relaxed the limits for the regular users, so occasionally one of their posts slip through.