you have an unlimited ball of fire...

[Scarim Coral]

I would go to a anime convetion and cosplay as Ryu from Street Fighter while performing that in a open field. (I don't want to kick out or somehow burn the place down!)

 

[The Funslinger]

a flame in my hand, you say? I would use it to start some kind of combustion related confrontation...

 

[The Funslinger]

I throw it at my DM and scare the shit out of him for not letting me play a monk!

What kind of lame DM doesn't let you play monk?

They may be the most fun to play, other than a properly kitted-out wizard of course.

He's not allowing them to be played because he doesn't like them (claims they are OP).

Monks aren't OP. Look at the average amount of damage a high-level fighter with magical weapons puts out. A monk doesn't use weapons, he uses his fists, and his damage output needs to be upped in order to match.

And look at what a high-level magic user can do, both damage-wise and special abilities. If your DM thinks Monks are OP, he doesn't understand the mechanics well enough. Monks have the same issues as mages; they're both really weak at low levels. But, at high levels, both mages and monks become incredibly kick-ass.
The difference is that mages get resoundingly more kick-ass than any other class. It's a well-known fact that while a 20th-level fighter may be able to solo a CR20 monster, a 20th-level spellcaster could obliterate a whole host of CR20s all by himself.

It's discussions like this that make me wish I could play Dungeons and Dragons... stupid lack of fantasy nerds round here...

 

[Lawnmooer]

I'm tossing the sucker into the ocean and turn this ball of mostly-water (earth)

Though Earth isn't mostly water...

The surface of the Earth is, but the surface is only a small fraction of the entire thing.

On Topic:

I'd try to roll it across the floor to see if I can make a wall of fire, and to see if I can make the fire come and go as I please.

If I have control over it and can summon the infinite fire when ever I wanted I'd probably just use it to light my friends cigarettes when their lighter has ran out, (Which seems to be all the time) use it as a torch, warm my friends up with it and maybe try and earn some money by being a street performer in the times where I have to wait between an hour and a half and two hours for my bus home from college.

Possibly experiment with Rocket Boots/Roller Blades/Skateboards.