First of all, and the far most easy thing you can do with someone's IP is actually locate where this IP is generated. Many websites can do this for you while you just insert the IP address you have.
That is for the 100% legal part.
(As basicly any website records your IP, and therefor acceses that info)
You can also easily play some tricks with your friends using your "comand prompt"
(=> type in cmd in your "run" thingie )
Eg : DoS attacking them; in English : overflowing them with info, and thus eating up their broadwith, so they suffer heaby lag. I advise to you not to try this when you don't have a fast connection yourself. And don't try to overflowing servers (say Google) with your home PC as you'd crash even before those website gets a few ms of "extra" lagg.
This however can easily be defended by your victims firewalls.
There are many, many, many, many other things you can do with IPs , but those things are more advanced.
Actually your asking us : "what funny things can you do when you have someones name ?"
Chat with our AI personalities
It depends on the circumstances as to what you are doing. If they are running a server you may be able to connect to them. ie: a game, or a website. Alternatively you may be able to find their general location by looking it up-- This is their ISP or where their server is connected to the internet. If connected together via lets say COd, you may be able to send information to and from them.
They can try to break in to your computer or deny you access to internet (through a denial-of-service attack, flooding your computer with so many requests that it buckles under the load). A good firewall is a reasonable defense, but a skilled and dedicated attacker may well find a way through, especially if you don't know much about network security yourself.
They can also tell approximately where you live. Not down to the street, but at least down to country and city, perhaps also down to borough and ISP. Getting your actual address from the ISP would normally require a court order or similar.
you hack into them using botnet or cmb, u can cannect to them using remote access or use a Trojan on them if ur good.
~thud~
Mostly anything they wan't. They can scan it for open ports, Search for vulnerable application running on your system, Netbios hack, lots of things don't let anyone have this information.
Well, It is possible. It's pretty much just like viewing someones aura.
I recommend you check the games on Google Play. There are tons of funny games, such as "Duck Killer" @ https://play.google.com/store/apps/details?id=jh.duckkiller2
If you play with multiple accounts on the same world you will be banned. I recommend you stop looking for this 2nd account
on a horse yes haking into someones account on a site is bad and is bad for you reputation it is a cyber crime. it detructs many of lives
If you live in the United States then yes, but not in Canada or Switzerland or France, or anywhere in Europe except Germany and the UK.