It appears that Easter is at the end of March this year…
echo Easter is `echo 2005 '[ddsf[lfp[too early]\
Pq]s@1583>@ddd19%1+sg100/1+d3*4/12-sx8*5\
+25/5-sz5*4/lx-10-sdlg11*20+lz+lx-30%d[30+]s\
@0>@d[[1+]s@lg11<@]s@25=@d[1+]s@24=@se44le\
-d[30+]s@21>@dld+7%-7+[March ]smd\
[31-[April ]sm]s@31<@psnlmPpsn1z>p]splpx' | dc`
(Thanks to Stewie for that scary nugget of code!)