Agonalia -- the fourth and final occurrence of this festival in the Roman calendar; like all instances, the Rex Sacrorum would sacrifice a ram in the Regia, but on this occasion, the sacrifice was apparently in honour of Sol Indiges.
Septimontium -- a somewhat obscure festival apparently originally only celebrated by the 'montani' (i.e. the 'hill-dwellers') which involved sacrifices on each of Rome's seven hills.
287 -- martyrdom of Fuscian (and others)
302 -- martyrdom of Pontian