Tournament
If you need a good combat session but don't have an enemy hoard at hand, local tournaments/competitions are a brilliant session-specific device. They allow a skill and combat-heavy session within any story arc.
The scope can be anything you want: combat, profession, cross-country challenge or a bit of everything. Combine individual challenges with team ones.
You can interweave socializing into a three day tournament during which the players can make new friends/contacts for the future. The events feature on Scabard is ideal for planning this type of plot.
Arena Challenge
Less benign than a tournament, an arena challenge is a fight for survival and escape. You will have to create a plausible scenario to get your party into the situation to start with, but after that it is pure combat. I once used trial by combat as the pretext.
Dropping this type of session onto players unexpectedly has additional impact and is a good way to change the tempo if sessions have been a little slow and combat light for a while.
It can also strengthen your party by requiring them to assist each other to survive.
A Week At Court
At the opposite end of the spectrum, a court (or diplomatic establishment) is an environment where weapons are never drawn in anger and may not even be permitted at all.
This can be instigated fairly easily by an unexpected (but flattering) invitation. If your sessions have involved a lot of combat rolls, immersing your players in a purely RP setting can offer a welcome change of pace.
Verbal sparring, social upmanship and polite entertainments are the order of the day. Within this setting you can work in a mystery or murder plot for your characters to solve- necessary before they will be allowed to leave in any case.
Framing one or more party members for the deed could add some spice to proceedings.
A Spiritual Retreat
Similar to the above, taking some time out for spiritual enlightenment offers a chance to set weapons and dice aside in favor of peaceful meditation.
A group meditation can lead to a shared experience where you can create any type of short plot you wish. One option in a meditative scenario is to place characters in roles (even bodies) completely different to that they normally play.
A moral dilemma can be particularly useful if you want to get your players talking and interacting in character. Imposing a set timescale (timer on the table) can represent the period of meditation and also ensure they reach a conclusion within one session.
Hopefully some wisdom will follow and a gift of some type, suited to each player, can reward them for the experience.
