Temporarily block IP address -

Simple example, but you could do something like this to define your schedule. Needless to say, if you want a more complicated schedule you'd need to have more complicated conditions e.g. $curTime is greater than timeA and less than timeB

set curTime "[clock format [clock seconds] -format %H%M%S]"
set pm 120000

if { $curTime < $pm } {
     It's AM - Do something
} elseif { $curTime > $pm } {
     It's PM - Do something
}