Related in definition to the killtacular in Halo 3 and Halo Reah or the kill frenzy in Halo 2. The Chilltacular does everything the killtacular does, but only chiller. There are 2 associated usages of chillatcular. The first is if 5 really chill and cool things happen back to back. The second is if something is so chill and so cool that it is as cool and chill as 5 compounding chill and cool events, then it is a chilltacular. Chilltaculars are often thought of as douchey or faggoty due to their association to life changing video games; however, only true bros use the word chilltacular. Therefore, the usage of chilltacular correlates to one's status as a brosef.
Man this weekend was so Chilltacular I met an awesome girl, partied hard, played some Halo, laxed a bit, and hung out with my brosefs.