Great place to get xp when you hit 36.....Guaranteed to work!
There is a mission in founders falls from a contact named "maren mcgregor" near the mutant enhancement contact,under a tree(need to be 38 to get the mission,but only 36 to get on a team for it because of min lvl for abandon sewers).
Get the mission from her,it will be to kill 150 rikti in the sewers (best place to get there would be steel canyon).Once inside the sewers go to your right and in the door,you will now be in the abandoned sewer network.There will probably be people in here doing the same thing as you are,so group with them,or some people you know to be good hunters(more people lvl 38-40=more missions,and you only have to kill 150 rikti if you do it all at the same time as everyone else).Make your way down the sewers until you reach a marker on your map for "the underworld" there should be rikti on the way and near that area.
Once you have killed all the rikti,return to the contact and get the other mission she has for you,it will be a mission to "defeat the hydra head",return to the sewers,(best to have someone with tp wait near the underworld marker so you dont have to run all that way again).Go to the door,there will be a computer near the door,click on that and the timer will start.
Go in the door and make your way down to the left and you will see a ledge and some rikti near the ledge,kill them but careful not to aggro any other mobs.In front of you on another platform you will see a monster called the "hatched kraken" (similar to the one found in perez park,but he will be lvl 42,so a good team cannot be stressed enough,bubbles help lots). Once he is dead (the xp for this kill should range from 35k-100k),have the person with tp drop all the way down to the bottom where the hydra head is,careful...he hurts...lots..one hit kill if you are squishy (controllers/fenders,this means you!).
Teleport all of the members of your party to a safe location prefferably near one of the generators guarded by more rikti,make a nice space to fight in,and dont kill the generator,it will alert the rikti and makes for more rikti to kill.From the generator,have one of the tankers go look for another one of the kraken and pull him back to your groups location,(i usually go in a counter-clockwise direction around the outside of the hydra head in the middle).
There are 5-7 kraken in each mission giving insane amounts of xp per each killed.The last one is up top some where,send someone with invisibility and fly to go find him (sorry,written on the fly,dont have exact location :p).Once you have killed all of the kraken,log out of the game and log back in,it will return you to outside of the mission door and the mission will be failed,but you can go right back to the contact and get the same mission to kill the hydra head as many times as you want between the levels 38-40.
This mission takes my team about 15 minutes start to finish but take your time,you arent actually completing the mission,so you got time to spare..just check the clock once in a while to make sure

.Great xp,great influence,i made about 8 million influence in a day once from doing it over and over.All i ask for this information is that after you are done doing it for the day (or night,lol) go to atlas and give some influence away to the noobs under the statue.It is kinda a ritual we do with my Supergroup,and would like to keep it going (plus its just nice to do,and they get sooo excited when you offer them a bunch of influence).The group i go down there with has no problems,and have kept the deaths to a very minimum (only deaths because of personal fault,not whole groups i.e. invulnerable tankers power unstoppable going off at the wrong moment wont be fun,drains all your life and endurance when it wears off).I always bring with at least 1 tanker(to hold aggro on the kraken and to pull),2 defenders (for medicinal purposes,prefferably with bubbles)2 scrappers (for dmg)and 1 controller (prefferably with bubbles if defender doesnt have them,but double bubbles are nice too :p).
Well,i hope this makes someones day,and i dont get flamed too much for the possible wrong place for a post of this nature and/or (but not limited to) my punctuation,my spelling(?),my "( )",and my blatent exploit spoiler for xp at this lvl...Thanks guys and delete this post if desired moderators,wont hurt my feelings at all :p.........
WARNING:BE PREPARED TO LEVEL QUICK DOWN THERE.Wont say how much they give out per kraken,but i assure you,its alot,xp and influence wise.Happy hunting and remember,DEBT IS THE ENEMY!