If your getting bored of grinding, I'd definitely suggest hopping in a skype chat with a friend and go try out some bosses.
You didn't specify the gear you have available but here are some bosses that I think you could handle with one or two friends quite easily.
-Chaos Elemental (Fun boss to kill + now it has a potential to drop the old pvp loot like vesta longswords or brawling gloves)
-Kalphite Queen (Not the best drops, but it is something to do if you haven't done it already)
-King Black Dragon (More of something to do for fun, since mithrils have better drops and are easier to kill)
-Revenants (A personal favorite of mine, just be sure to watch out for clans

)
-Dagganoth Kings (These might be a little tricky for you, but there very fun and to this day they're a great source of money)
-Giant Mole (No challenge here, but you would get some money and some fast exp)
-God Wars Dungeon (Might be a little tricky for you, considering you probably don't have access to overloads or turmoil, but in all honesty, it just makes it that more fun when it's a challenge. Also, I'm sure you could manage to get a couple of kills once you and your friends figure out what to do)
That's about it, nothing else outside of dungeoneering/quests really comes to mind except for nex and the corpereal beast (both of which will require you to have higher stats).
If your having troubles figuring out what to bring to each boss, visit this youtube channel
http://www.youtube.com/user/RuneSharkVideos they have strategy guides on every boss.
Finally, if your having troubles finding friends to go bossing, I'd suggest making a thread asking if anyone wants to go bossing with you. ^_^