A range of targets is good also think about a range of difficulties so that everyone can be challenged. Is this a dark sky challenge or a light polluted backyard challenge
at least 1 object suited to beginners
at least 1 object that will challenge experienced observers
at least 1 object suited to small telescopes - we don't all have big 6" dobs
the rest ranging somewhere in between
optional a binocular challenge or a naked eye challenge
Not much time left in January. Some nominations in no particular order.
Mars polar cap
trapezium in M42
k Puppis
Probably need the more experience members to nominate the hard stuff.