There's like 20 different votes you can make in warsow. Some of them are:
Lock/unlock teams
Change map
Restart map
Kick
Mute
Enable/Disable warmup
Warmup time
Gametype (ctf, tdm, duel, ffa, clan arena)
Timelimit
There's a main cvar that enables/disables voting, then for each different type of vote there's a cvar to disable that particular vote. i.e. g_disable_vote_kick, g_disable_vote_mute. Things like gametype let admins specify which gametypes are available to be voted. i.e. g_votable_gametypes "tdm ctf".
There's also a g_vote_percent which lets you specify what percentage is required for any vote to pass. That would be the percentage of the entire server, so you end up with things like 16 players on a server, 8 vote yes, 0 vote no, 8 don't vote and vote fails.
If you're a player, you vote by: /callvote map wdm1 or /callvote warmup 0. Doing just a /callvote timelimit shows the current setting, and if applicable it will list all of the available options. It's not perfect and gets abused on pub servers, but for private servers it's good because you don't have to give out rcon passwords to anyone that wants to change maps or switch from tdm to ctf. Also, there's only one vote ever happening at once. The votes each last 30s or so.