Madden 64 

View ending sequence 
At the EA logo when the game is first started:
hold L + R + Z.

Always win coin toss 
When the referee tosses the coin:
press Down for "tails", then press Up to select "heads" approximately two seconds before the coin lands.
If done correctly, both sides of the coins will be "heads".

Touchdown show-off 
After entering the endzone:
press C-Left to perform a touchdown dance.

Random team selection 
At the team selection screen:
select Exhibition mode and press C-Up + C-Right.

Cheat Codes 
Select season mode:
and enter the front office menu. Then, create a player and enter one of the following names.
Note: "_" indicates a space. Use the "Continue" option and save the player.
Press B(2) to return to the game 
selection screen and choose exhibition mode to access the cheat effect.

Name               What It Does
Tiburon            Large players
Elec_Arts          Larger, more powerful players
Sixties            1960's teams
Seventies          1970's teams
Eighties           1980's teams
B_Howlie           1997 AFC Pro bowl team
Lei                1997 NFC Pro bowl team
AT_Madden          All-Time Madden team
Stats_Men          Statistical leaders team
Maitland           Tiburon stadium
San_Mateo          EA stadium