Recently my wife and I were able to travel to attend a wedding of some friends. It was a destination wedding and so, on the back of the excitement of seeing two people commit themselves to each other was the added interest of exploring a new environment - an adventure.
Exploring the new is a great way to change mindsets, expand thinking, recalibrate perspective and is important to delve into regularly. My previous post about routine may seemingly go against the spontaneity of adventure, and yes in a number of ways it does. If the adventure experience takes time away from the routine or takes you to a different setting where your usual routine isn't possible, the two concepts do seem to be at odds with each other; however, it is the adventures that make us aware of things we may not have considered - new things that may add more to our lives. They cause us to push our boundaries, making our world larger.
These adventures don't have to be big to achieve the goal of excitement/novelty and bring about intellectual stimulation. While a 6 week holiday would be a fantastic adventure, maybe just doing something a little out of the norm during your day can have a similar effect. Maybe you get coffee from the same place each day with the same barista, perhaps instead of ordering and leaving it might be an adventure to take 5 minutes to chat with them and find out what study they are doing etc. (I'm sure they would start remembering your order!). Maybe you walk to/from work and could change your route once a week - it might take longer, but there will be new sights, smells and even potential opportunities (I did just this the other day and ended up finding a new local pizza shop that looks pretty good!)
If you are very big on routines (like me), it might work to schedule in "adventure time", specifically putting aside time to try something new each day/week/month. While these adventures can seem to cut in on the progress of the day-to-day study/work/exercise etc. schedule, the adventures are where testing occurs, character is built, relationships are strengthened and memories are forged.
Don't leave out "adventure days!" (a term coined by my wife for days when the kids are out of day-care and we spend time together)