A rounded, solid wooden or hollow aluminum bat. Wooden bats are traditionally made from ash wood, though maple and bamboo is also sometimes used. Aluminum bats are not permitted in professional leagues, but are frequently used in amateur leagues. Composite bats are also available, essentially wooden bats with a metal rod inside. Bamboo bats are also becoming popular.
This is the drill we ran all through high school. It is the most time effective and skill intensive way to warm up a team, but your boys must be able to play catch! Fungo-ers stand in the "fungoe circles" that any good field has (and if it doesn't, you know where they're supposed to be - just outside of the home-plate dirt circle, towards the dugouts). The catch to this method is this - you have two first basemen, allowing both sides of the infield to throw across. Herein lies the only danger - one of the firstbasemen has a lengthy throw back to a shagger, so caution must be excersized (a catcher with a good head on his shoulders really helps).
If fungoes are a ball tossed into the air by a batter and then struck as it comes down then a fungo bat is a baseball bat used for hitting fungoes. To go into more detail, a fungo bat is a long, lightweight baseball bat used by coaches (or parents) during pregame hitting or practice to help them hit grounders and pop flys with more consistency and less fatigue. To be one of the best in baseball, countless hours of practice are a must and fungo bats are intended for both infield and outfield practice. Plus, they help tremendously with control and accuracy so that coaches and parents can place a ball where they want when they want.