This command adds 4 new TNT-related items to troll your friends with! Grab a command block by using the command /give [username] command_block and paste in this command:

(Note: you can quickly highlight the command by triple-clicking it)

/summon MinecartCommandBlock ~ ~1 ~ {Command:kill @e[type=MinecartCommandBlock,r=1],Riding:{id:MinecartCommandBlock,Command:setblock ~ ~-1 ~1 redstone_block,Riding:{id:MinecartCommandBlock,Command:setblock ~ ~ ~1 command_block 0 replace {Command:fill ~ ~-3 ~-1 ~ ~ ~ air},Riding:{id:MinecartCommandBlock,Command:"/gamerule commandBlockOutput false",Riding:{id:MinecartCommandBlock,Command:"/tellraw @p [\"\",{\"text\":\"Right-click the green sign to start trolling!\",\"color\":\"green\"}]",Riding:{id:MinecartCommandBlock,Command:"/tellraw @p [\"\",{\"text\":\"Trolling and griefing devices by lettuce11\",\"color\":\"green\"}]",Riding:{id:MinecartCommandBlock,Command:"/tellraw @p [\"\",{\"text\":\"[!] Added \"Trolling Devices\" by lettuce11\",\"color\":\"green\"}]",Riding:{id:MinecartCommandBlock,Command:setblock ~3 ~-2 ~ redstone_block,Riding:{id:MinecartCommandBlock,Command:setblock ~3 ~-2 ~-1 command_block 0 replace {Command:fill ~ ~ ~1 ~2 ~1 ~1 stone},Riding:{id:MinecartCommandBlock,Command:setblock ~3 ~-2 ~1 command_block 0 replace {Command:fill ~ ~ ~-1 ~2 ~1 ~-1 redstone_block},Riding:{id:MinecartCommandBlock,Command:setblock ~4 ~-2 ~-1 command_block 0 replace {Command:"/execute @e[type=Spider,name=Hover-TNT] ~ ~ ~ /summon PrimedTnt ~ ~1 ~ {Fuse:80,Riding:{id:\\\"Bat\\\",Attributes:[{Name:generic.movementSpeed,Base:50}],Silent:1,ActiveEffects:[{Id:14,Amplifier:1,Duration:2000,ShowParticles:0b}]}}"},Riding:{id:MinecartCommandBlock,Command:setblock ~4 ~-2 ~1 command_block 0 replace {Command:"/kill @e[type=Spider,name=Hover-TNT]"},Riding:{id:MinecartCommandBlock,Command:setblock ~5 ~-2 ~-1 command_block 0 replace {Command:"/execute @e[type=Bat,name=Bomber-Bird] ~ ~ ~ /summon PrimedTnt ~ ~-1 ~ {Fuse:80}"},Riding:{id:MinecartCommandBlock,Command:setblock ~5 ~-2 ~1 command_block 0 replace {Command:"/execute @e[type=Creeper,name=Trolling-Creeper] ~ ~ ~ /summon Creeper ~ ~1 ~ {CustomName:\\\"trolololololol\\\",powered:1,ExplosionRadius:20,Fuse:1,Attributes:[{Name:generic.movementSpeed,Base:1},{Name:generic.followRange,Base:50}]}"},Riding:{id:MinecartCommandBlock,Command:setblock ~3 ~-1 ~-1 command_block 0 replace {Command:"/kill @e[type=Creeper,name=Trolling-Creeper]"},Riding:{id:MinecartCommandBlock,Command:setblock ~3 ~-1 ~1 command_block 0 replace {Command:"/execute @e[type=Silverfish,name=TrollBomb] ~ ~ ~ /setblock ~ ~ ~ minecraft:mob_spawner 0 replace {EntityId:PrimedTnt,SpawnData:{CustomName:\\\"trolololololol\\\",CustomNameVisible:1,Fuse:80},SpawnCount:10,SpawnRange:20,RequiredPlayerRange:20,Delay:0,MinSpawnDelay:0,MaxNearbyEntities:1000}"},Riding:{id:MinecartCommandBlock,Command:setblock ~4 ~-1 ~-1 command_block 0 replace {Command:"/kill @e[type=Silverfish,name=Trollbomb]"},Riding:{id:MinecartCommandBlock,Command:setblock ~1 ~ ~ wall_sign 4 replace {Text2:"{text:\\\"Trolling Devices\\\",color:black}",Text3:"{text:\\\"By lettuce11\\\",color:black}"},Riding:{id:MinecartCommandBlock,Command:setblock ~1 ~-1 ~ wall_sign 4 replace {Text1:"{text:\\\"\\\",clickEvent:{action:\\\"run_command\\\",value:\\\"/give @p minecraft:spawn_egg 64 52 {HideFlags:1,display:{Name:Hover-TNT,Lore:[A Spider-Powered Hovering TNT!]},ench:[{id:51}]}\\\"}}",Text2:"{text:\\\"[Get Items]\\\",color:green,clickEvent:{action:\\\"run_command\\\",value:\\\" /give @p minecraft:spawn_egg 64 65 {HideFlags:1,display:{Name:Bomber-Bird,Lore:[A super-destructive griefing device - use wisely!]},ench:[{id:51}]}\\\"}}",Text3:"{text:\\\"\\\",clickEvent:{action:\\\"run_command\\\",value:\\\"/give @p minecraft:spawn_egg 64 50 {HideFlags:1,display:{Name:Trolling-Creeper,Lore:[A super-fast highly-destructive Creeper that explodes instantly!]},ench:[{id:51}]}\\\"}}",Text4:"{text:\\\"\\\",clickEvent:{action:\\\"run_command\\\",value:\\\"/give @p minecraft:spawn_egg 64 60 {HideFlags:1,display:{Name:TrollBomb,Lore:[The Ultimate trolling Device!!]},ench:[{id:51}]}\\\"}}"},Riding:{id:MinecartCommandBlock,Command:setblock ~1 ~-2 ~ wall_sign 4 replace {Text2:"{text:\\\"[Destroy Machine]\\\",color:red}",Text4:"{text:\\\"\\\",clickEvent:{action:\\\"run_command\\\",value:\\\"fill ~ ~-1 ~-2 ~6 ~2 ~2 air\\\"}}"},Riding:{id:MinecartCommandBlock,Command:fill ~2 ~-2 ~-2 ~6 ~-1 ~2 stained_glass 10 replace obsidian 0,Riding:{id:MinecartCommandBlock,Command:fill ~2 ~-3 ~-2 ~6 ~ ~2 obsidian 0 hollow,Riding:{id:MinecartCommandBlock,Command:gamerule commandBlockOutput false,Riding:{id:MinecartCommandBlock,Riding:{id:FallingSand,Block:activator_rail,Time:1,Riding:{id:FallingSand,Block:redstone_block,Time:1,Riding:{id:FallingSand,Block:stone,Time:1}}}}}}}}}}}}}}}}}}}}}}}}}}}

Have fun :)