Reddit has a subreddit Guns are cool which in turn contains the MASS SHOOTINGS IN 2013 page. I pulled those data to see if there was anything of interest to plot or examine. I ended with modelling the frequency of shootings (once a day, Poisson distribution), and number of victims per shootings, a mixture of distributions, 2% of shootings are from a Poisson distribution with Lambda=15.

Data

Data are 264 records, spanning from January 1st to September 19th at the moment or writing. Rule for entry in this table: ‘The only requirement is that four or more people are shot in a spree, likely without a cooling off period. This may include the gunman himself (because they often suicide by cop or use a gun to kill themselves to escape punishment), or police shootings of civilians around the gunman. The reasoning behind the latter being that if the shooter is arrested, he will often be charged with injuring people the police actually shot, as that is a foreseeable result of a shooting spree.‘ The data are not entered with the objective of machine processing, for instance records up to 6 show there are sometimes number of death, sometimes injured, sometimes both, in either order. The final entries on a row are location and state, the first are number and date, between it is messy, with random usage of commas and random number of entries between them.
Number 1: 1/1/13, Julian Sims, 4 injured, McKeesport, PA
Number 2: 1/1/13, Unknown, 1 dead 3 injured, Hawthorne, CA
Number 3: 1/1/13, Desmen Noble, Damian Bell, 1 dead 4 injured, Lorain, OH
Number 4: 1/5/13, Sonny Archuleta, 4 dead, Aurora, CO
Number 5: 1/7/13, Sandra Palmer, 2 dead 2 injured, Greensboro, NC
Number 6: 1/7/13, Herbert Bland Jr., 23, 3 dead 1 injured, Dinwiddie, VA