I have completed the first public beta version of freezetag mod which will be included in version 2.2 of xMod. You may try it out at: 188.8.131.52
It is the the last map in the rotation on ctf3.
The general idea is the team that is "IT" needs to kick all the opposing team members to freeze them. This freeze ability lasts 60 seconds (cvar) and can only be removed by time or a teammate kicking you. By freezing the entire team at once your team scores a point.
The team that is "not IT" just has to run to the opposing team's base and touch the flag. This makes them protected from the freeze ability of their enemy, but they can still be killed normally. If they die they must run back to the flag to become protected again. They will score a point if they can get their entire team protected.
FYI in future versions (ie. tomarrow when I get around to it) I will be making it so people can not join teams until the break point inbetween rounds to prevent unfair advantages.
Give it a try and let me know what you think