The NIT - What's this all about?
Teams not qualifying for the NCAA tournament have the opportunity to be invited to one of three other postseason tournaments:
The NIT features a 32-team field chosen right after the NCAA chooses the 68 teams in its tournament.  It awards automatic bids to regular season conference champions who do not otherwise go to the NCAA tournament. Also, the first 4 teams out of the NCAA tournament become automatic 1 seeds in the NIT.

The CBI features 16 teams and the CIT has 32 teams exclusively from mid-major leagues or lower (only 26 teams participated in 2016 and 2017).  The CIT requires teams to have a .500 record or better while the NIT and CBI do not have such a requirement.  The CIT also doesn't place teams in a bracket, opting to place teams in matchups after the previous round has concluded. 

Schools have been known to decline an invitation to the CBI/CIT tournaments due to the lack of interest in playing in a third-tier tournament (e.g., "We're Indiana. We don't play in the CBI.") or the pay-to-play nature of these tournaments.

The Vegas 16 was a 5-day postseason tournament featuring 16 teams playing all games in Las Vegas in the week leading up to the Final Four. The 2016 edition only featured 8 teams in a 3-day tournament. It was cancelled for 2017 and it's unclear if it will be revived in 2018.
 
To get a feel for what kind of teams are involved, these were the 2017 participants along with their record and RPI.


The 2017 NIT, CBI and CIT Teams

NIT CBI
CIT
33
Illinois State
Missouri Valley
27-6
94
San Francisco
West Coast
20-12
73
UNC Asheville
Big South
23-9
45
Texas-Arlington
Sun Belt
25-8
102
George Washington
Atlantic 10
19-14
96
Furman
Southern
21-11
49
Monmouth
Metro Atlantic
27-6
103
George Mason
Atlantic 10
20-13
104
Georgia State
Sun Belt
20-12
52
Georgia
SEC
19-14
122
Georgia Southern
Sun Belt
18-14
129
Albany
America East
21-13
53
California
Pac-12
21-12
148
Eastern Washington
Big Sky
22-11
130
St. Peter's
Metro Atlantic
19-13
54
Houston
American
21-10
152
Wyoming
Mountain West
18-14
159
Texas A&M-Corpus Christi
Southland
20-11
58
Akron
MAC
26-8
156
Toledo
MAC
17-16
164
UT-Martin
Ohio Valley
21-12
60
Belmont
Ohio Valley
22-6
158
Green Bay
Horizon
18-13
165
UMBC
America East
18-12
62
College of Charleston
Colonial
25-9
168
Rice
CUSA
22-11
167
Canisius
Metro Atlantic
18-15
64
Illinois
Big Ten
18-14
177
Stony Brook
America East
18-13
169
Ball State
MAC
21-12
65
BYU
West Coast
22-11
183
Coastal Carolina
Sun Belt
16-17
170
Samford
Southern
19-15
66
Colorado State
Mountain West
23-11
184
UMKC
WAC
17-16
173
Liberty
Big South
19-13
67
TCU
Big 12
19-15
205
Utah Valley
WAC
15-16
176
Houston Baptist
Southland
17-13
68
Clemson
ACC
17-15
212
Loyola-Maryland
Patriot
15-16
178
IPFW
Summit
19-12
69
Central Florida
American
21-11
250
Illinois-Chicago
Horizon
15-18
179
Texas State
Sun Belt
20-13
71
Valparaiso
Horizon
24-8
284
Hampton
MEAC
14-16
180
Fairfield
Metro Atlantic
16-14
72
Boise State
Mountain West
19-11




185
Weber State
Big Sky
19-13
75
CSU-Bakersfield
WAC
22-9




203
Stephen F. Austin
Southland
18-14
76
Fresno State
Mountain West
20-12




207
Idaho
Big Sky
18-13
77
Ole Miss
SEC
20-13




229
USC Upstate
Atlantic Sun
17-15
78
Alabama
SEC
19-14




232
Lamar
Southland
19-14
79
Indiana
Big Ten
18-15




242
Norfolk State
MEAC
17-16
80
Richmond
Atlantic 10
20-12




247
Campbell
Big South
17-17
81
Iowa
Big Ten
18-14




257
St. Francis (PA)
Northeast
16-16
83
Utah
Pac-12
20-11




269
Cal State Fullerton
Big West
17-14
84
Syracuse
ACC
18-14




291
Jacksonville
Atlantic Sun
17-15
95
UNC Greensboro
Southern
25-9








99
Colorado
Pac-12
19-14








106
Georgia Tech
ACC
17-15








109
Oakland
Horizon
24-8








116
South Dakota
Summit
22-11








133
UC Irvine
Big West
21-14









Automatic bids listed in bold.

Contact: bracketproject@gmail.com