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).
Fungo bats are, simply put, a long, skinny, and lightweight baseball bat used for fielding practice. Typically, they are around 34 to 37 inches in length and between 17 and 24 ounces in weight, give or take a couple of ounces. They will also almost always feature a 2 1/4 inch barrel diameter to allow for more control during a swing. As you can tell, fungo bats are longer than a normal baseball bat and much more lightweight in comparison. Most fungo bats are going to be made up of ash wood while there are some maple and bamboo wood fungo bats, some composite wood fungo bats, and very few aluminum alloy fungo bats. Almost all of these designs will be under $100 with very few eclipsing that mark. 
“They’re not moving, their feet are apart, their gloves are on the ground, backs are flat, and they’re working down to up, out to in, basically a steady roll back and forth probably 15 to 20 each,” Bates said. “Then they’ll turn their body, work glove side for another 15 to 20, and backhand 15 to 20. No movement, really, just making sure we’re watching the ball roll into our glove, fielding it, and doing all the things fundamentally correct.”
As I had previously mentioned, the amount of teaching points is limitless.  The length of the game will really depend on how often you stop the action in order to discuss points related to base running, backing up throws, fielding techniques, and etc.  If you have assistant coaches, have them distributed throughout the field in order to help with certain teaching points on the spot, thus eliminating full stoppages of the game.  Now get out there and start putting the “FUN” back into fungo. I know that’s pretty corny, but I couldn’t help myself 🙂
Another variation of playing is setting a target (i.e. home plate), and that is the hole for the entire game. For the entire game players go to a different part of the field and try to hit home plate in the fewest strokes.To make the game more interesting players can create certain hazards or obstacles that the players must avoid hitting while making their shot. If a player hits a certain hazard then they may be penalized one stroke, a player can also lose a stroke if he loses their ball while taking a shot.