I guess there is not a way to "end the game", but there are several raids that go on at the very high-end of play. They range from 2x, 3x, or 4x groups, sometimes requiring months to gain access.
Even so, completion of these raids does not end the game or lock anything out. In fact, many raid guilds repeat their raids over and over to get the best loot drops possible. Some zones have a day or week lockout.
Raiding guild have regular schedules of making a circuit aroun dparticular raid zones, even scheduling a few days off during the week.
For those players capped, there will soon be a "Alternate Advancement" (similiar to EQ1) system where you can gain exp and use it to obtain abilities of stat boosts, instead of levels.