It's bizarre looking at an image and then getting a feeling that you have seen it before, only to check the anime and realize you watched the entire series and didn't remember.
Anyways, dun listen to all those pleb suggestions (except that one with Suzumiya Haruhi...and the Parasyte one too I guess). Working under the basis that you can finish at least a one cour anime per day (so 12 epi/day), here are 98 anime series that should last you the summer. And as a bonus, some one shots from shit like Anime Mirai.
Series:
01) Akatsuki no Yona
02) Amagi Brilliant Park
03) Angel Beats!
04) AnoHana
05) AnoNatsu
06) Ao Haru Ride
07) Barakamon
08) Black Cat (manga is better by tons)
09) Haganai
10) Haganai Next
11) Kawaisou
12) Btooom!
13) Chuunibyou
14) Cross Ange
15) Death Parade (Watch with Death Billiards)
16) Elemental Gerade
17) Elfen Lied
18) F/SN
19) F/SN UBW
20) F/Z
21) F/Z 2
22) Fate/Kaleid Liner Prisma Illya
23) Fate/Kaleid Liner Prisma Illya 2wei
24) Fractale
25) Gekkan Shoujo
26) Golden Time
27) Gosick
28) Grisaia no Kajitsu (and the running second season if you want)
29) Guilty Crown
30) Haiyore! Nyaruko
31) Haiyore! Nyaruko W
32) Hataraku Maou-sama!
33) Hellsing
34) Hellsing Ultimate
35) HenNeko
36) Higashi no Eden (and two movies)
37) Hitsugi no Chaika
38) Hitsugi no Chaika Avenging Battle
39) Ichigo 100%
40) Inou-Battle
41) Isshuukan Friends
42) Junketsu no Maria
43) K-On! (please turn off brain, once you finish this, there is much more moe to be had, but that is a different list)
44) Kaiba
45) TWGOK
46) TWGOK 2
47) Kannagi
48) Katanagatari
49) Kemono no Souja Erin
50) Kemono no Souja Erin
51) Kemono no Souja Erin
52) Kemono no Souja Erin (It's 50-ish episodes, and I'm recommending it 4 times, fucking watch it and be sure to get past the first 6 episodes before you decide on binning or continuing)
53) Kill La Kill
54) Parasyte
55) Kotoura-san
56) Kure-nai
57) Kyoukai no Kanata
58) Kyoukaisenjou no Horizon
59) Kyoukaisenjou no Horizon II
60) Log Horizon
61) Log Horizon 2
62) Love Hina
63) Mahou Sensei Negima
64) Madoka Magica
65) Mahouka
66) Majimoji Rurumo
67) Medaka Box
68) Medaka Box Abnormal
69) Mekakucity Actors (BD version)
70) Mermaid Forest
71) Midori no Hibi
72) Mikakunin de Shinkoukei
73) Mirai Nikki
74) Mondaiji-tachi ga Isekai kara Kuru Sou Desu yo?
75) Mushi-Uta
76) Mushishi
77) Mushishi Zoku Shou
78) Mushishi Zoku Shou 2
79) Nazo no Kanojo X
80) NHK ni Youkoso
81) Nijuu Mensou no Musume
82) Nisekoi
83) NGNL
84) Noein: Mou Hitori no Kimi e (fuck the teen angst)
85) Noragami
86) Oda Nobuna no Yabou
87) Spice and Wolf
88) OreImo
89) OreImo 2
90) OreShura
91) OreGairu
92) Ouran Koukou
93) Outbreak Company
94) Phantom Requiem for the Phantom
95) Rokujouma no Shinryakusha
96) Rozen Maiden series
97) Ryuugajou Nanana no Maizoukin
98) Saenai Heroine no Sodatekata
List of overly recommended I don't even give a fuck anymore but still justified recommends:
AirTV
Air Gear
Clannad
Black Lagoon
Claymore
Chaos;Head
Code Geass
Cowboy Bebop
Eureka Seven
FLCL
FMA Brotherhood
Kanon
Monogatari Series
Samurai Champloo
OneShot:
Buta
Captain Harlock
Dakera no Manazashi
Death Billiards (watch with Death Parade)
Kuro no Sumika: Chronus
Ojii-san no Lamp
Rakuen Tsuihou
Redline
Mini-series:
Danna ga Nani
Mangaka-san to Assistant-san
Miss Monochrome
Just Recommends:
Denpa Teki na Kanojo
Eve no Jikan (movie or series, the movie is just the series in one whole video)
HanTsuki
Mardock Scramble (3 movies)
Of course, 98+ entries isn't even enough.