@Chris / Telamon is adding in new mobs and stuff for the event. It is going to be a combined event (st.paddys/Easter) in a week or so. This happened a few years ago when Telamon got sick, he pushed back the st.paddys event and ran it the same time as the Easter. You will be made aware of the event once it is released. Town invasions are exactly that, an invasion. So being attentive in IRC or having friends that can tell you something is going down is a big plus.