Idea shamelessly stolen from capitu, but tailored to me for all of the fests I am following this year. Mostly HP fests, but a few Teen Wolf and other fandom fests thrown in.

January:
TW: stop_drop_howl starts posting the 8th
TW: twreversebang starts posting the 20th
SH: come_at_once starts posting the 25th

February:
HP: hpsolemnlysworn starts posting the 1st
HP: hprare_cliche Valentine's Fest start posting 1st
N/A: torino10154 is hosting a Porn Sunday on the 2nd
HP: do_me_veela starts posting the 14th
HP: hd_remix starts posting the 28th

March:
HP: daily_deviant's Birthday Fest starts posting the 1st
HP: hd_familyfest starts posting the 3rd
HP: hp_getlucky starts posting the 17th
HP: hd_hurtfest starts posting 21st

April:
HP: dracotops_harry starts posting the 1st
TW: reel_wolves starts posting the 2nd
TW: teenwolfremix2014 starts posting the 7th

May:
HP: hds_beltane starts posting the 1st
HP: charlieficathon Fest starts posting the 5th
HP: hp_kinkfest starts posting the 6th
LotR: hobbitstory Big Bang starts posting the 10th
HP: harrydracompreg starts posting the 11th
TW: twbigbang starts posting the 26th

June:
HP: hd_smoochfest starts posting the 1st
HP: hprarefest starts posting the 1st
XMen: xmenbigbang starts posting the 14th

July:
HP: hpholiday's Fantastic Men Fest starts posting the 1st
TW: scilesreversebg starts posting the 11th
HP: hd_tropes starts posting the 14th
HP: hd_cliche starts posting the 31st

August:
HP: hrholidays Summer of Love starts posting the 5th
HP: dm_asp_fest starts posting the 29th

September:
n/a: bbtp_challenge posts on the 1st
HP: hp_drizzle starts posting the 1st
HP: hp_silencio starts posting the 21st
HP: hd_fan_fair starts posting the 26th

October:
HP: samhain_smut starts posting the 1st
HP: hp_creatures starts posting the 15th

November:
Inception: i_reversebang starts posting the 1st
HP: serpentinelion's Glomp Fest starts posting the 1st
HP: hd_fanart Fest starts posting the 1st
HP: hp_sexstars starts posting the 1st
HP: hp_crossgenfest starts posting the 3rd
HP: interhouse_fest starts posting the 3rd
TW: tw_fallharvest starts posting the 3rd
Avengers: c_im_bigbang starts posting the 5th

December:
ST: ksadvent starts posting the 1st
ST: happy_trekmas starts posting the 1st
TW: tw_holidays starts posting the 1st
TW: teenwolf_bb starts posting the 1st
HP: hd_erised starts posting the 1st
HP: mini_fest starts posting the 1st
HP: hd_owlpost starts posting the 1st
XMen: secret_mutant starts posting the 6th
TW: sterek_big_bang starts posting the 7th
ST: startrekbigbang starts posting the 10th
HP: hrholidays starts posting the 24th
HP: daily_deviant's Kinky Kristmas starts posting the 1st