Carefully break a dozen eggs (keep carton for egg storage until Easter hunt) preserving at least 3/4 of the shell (good time to make a large omelette or something)
Wash/clean interior of shell. Let dry.
Paint eggs, let dry, then fill with confetti and glue/top the eggshell opening with colored tissue, "cone-head shaped", over opening. Hide eggs in yard. Let kids break or smash the confetti eggs on each other's heads. Fun.
(*) Cascarone
\Cas`ca*ron"\, n. [Sp. cascar['o]n.] Lit., an eggshell; hence, an eggshell filled with confetti to be thrown during balls, carnivals, etc. [Western U. S.]
Webster's Revised Unabridged Dictionary, © 1996, 1998 MICRA, Inc.