There are a few hotels around the University of Tokyo but many hotels in Tokyo.
You can find a hotel, which is close to one of the stations of the same subway lines as the station getting to the University of Tokyo (Hongo campus).
Subway stations getting to the Hongo campus are
Hongo-sanchome (E08 or M21), Todaimae (N12) or Nezu (C14) of this subway map.

[1] Hotel list
A list of several hotels can be found below.
The detail information, for example, the location by Google map, can be also found in 3,4,5,6,7,8,9) or/and Tripadvisor (Hotel 1,2).

Nearby hotels (we can come to HC2012 by walking or subway.)
No.    Hotel name       location      time by walking     per night  
to nearby station
Hotel 1 Forest Hongo Hongo5 min. 10 min.(Hongo-sanchome E08/M21)
5 min.(Todaimae N12)
~12,000 Yen
Hotel 2 Ueno Hotel Park Side Ueno15 min. 6 min.(Ueno)
1 min.(Yushima C13)
single ~10,000 Yen
twin ~14,000 Yen
Hotel 3 Hotel Kizankan Hongo10 min. 2 min.(Hongo-sanchome E08/M21) ~8,500 Yen
Hotel 4 Ueno Terminal Hotel Ueno20 min. 2 min.(Ueno) ~10,000 Yen
Hotel 5 Ueno First City Hotel Ueno15 min. 10 min.(Ueno)
1 min.(Yushima C13)
5 min.(Okachimachi)
~8,500 Yen
Hotel 6 Tokyo Garden Palace Ochanomizu25 min. 5 min.(Ochanomizu) ~10,000 Yen
Hotel 7 Ochanomizu St.Hills Hotel Ochanomizu25 min. 5 min.(Ochanomizu)
5 min.(Yushima C13)
~9,500 Yen

Other hotels (we need to take a subway.)
No.    Hotel name       location      subway info     per night  
Hotel 8 Hotel JAL City Yotsuya Tokyo Yotsuya 1 min. to Yotsuya-sanchome (M11) ~8,500 Yen
Hotel 9 Hotel Monterey HANZOMON Hanzomon 1 min. to Honzomon (Z05),
then change subway at Otemachi (Z08 to M18)
~8,500 Yen

Note that if you'll use subway in the morning, probably you will experience the famous "rush-hour" in Tokyo.

[2] Web site to reserve Hotel

Station name (to the Univ. of Tokyo)    Subway line       Famous stations/cites   
Hongo-sanchome(M21) Marunouchi Line Ochanomizu(M20), Ikebukuro(M25), Otemachi(M18), Tokyo(M17), Shinjuku(M08)
Hongo-sanchome(E08) Oedo Line Shinjuku-nishiguchi(E01), Ueno-okachimachi(E09)
Todaimae(N12) Tozai Line Komagome(N14), Korakuen(N11)
Nezu(C14) Chiyoda Line Yushima(C13), Shin-ochanomizu(C12), Kita-senju(C18), Omote-sando(C04)

[3] A tower shown in our poster: Tokyo skytree (height 634m)
You can visit this tower now.
The web site is available here.
The subway station is "Oshiage (SKYTREE)" (Z14 or A20).

Other travel information can be found here.