Something like this?:
init -9 python:
register_event("check_skill_yada_yada_yada_event", trigger_type="auto", locations=["all"], run_conditions=["hero.get_skill('sex') >= 200"], priority=101, dice=0, restore_priority=0, max_runs=1)
label check_skill_yada_yada_yada_event(event):
"Have some moar zex!"
$ hero.Sex += 200
return
Remember that events are reevaluated on next day, you'll need to click ND before the event triggers.