Personally I enjoy to regularly set myself new challenges and to try out new stuff. Following is a list with multiple interesting challenges and inspiring "Life Hacks" that you could try if you'd like to spice up your life a little. I will probably write about my motivation and experiences about some of the items below in some more detail in my blog.
If you know something I should add to the list, let me know!
Embrace the cold: Cold shower challenge
If you are very sensitive to coldness, there might be good news: It's all about the right training - you can change that. Read here about "The Iceman", Wim Hof who ran a marathon at the northpole - in shorts and barefoot. So if you want to build a new relationship with the cold read this and check out his website here. For the start I recommend cold showers - I started this a few month ago and definitely notice a positive effect on my cold-resistance. Additionally cold showers boost your health, wake you up instantly and make for an excellent will-power training. More info about the cold shower challenge here and here.
100 Push Ups
The idea is pretty simple: 100 push ups in 6 weeks. If you bring up the willpower to stick to the schedule it seems possible. I once got up to 80 until a cold pushed me back. Infos here.
Learning to do a handstand
If you've always wanted to be able to do a handstand, here is a method saying it's possible to learn this in a month. Currently working on this and slowly seeing progress. More info here and here.
Change to a motivational password
More of a life hack than a challenge: Make your password a daily reminder for something important to you. Read this inspiring post on the idea about it.
Try Meditation (for 10 days)
There are countless scientifically proven benefits of regular meditation and if you've never given it a chance, maybe it's time to try. For the start I recommend using the headspace app for guided meditations or to look for a local meditation group (often free). Read more about my thoughts on meditation in my correspondent blog post.
Alternative Sleeping Cycles
There are people that claim it is possible to reduce sleeping time to a total of 2 hours a day (30 min of sleep every 6 hours) without any negative side effects. Scientific evidence is actually in favor of multiple cycles and proves the positive effect of napping. I tried a 3 cycle rythm in Taiwan and it definitely reduced my total sleeping time. Sounds crazy, right? More info here and here.
Lucid dreaming
Lucid dreaming is the awareness during a dream that in fact you are dreaming. This enables you to actively take control and try out the crazy stuff, you wouldn't do in real life. While it seems that some people happen to experience this naturally once in a while (I don't unfortunately) there are people claiming its possible to train this. More info here and here.
Integrate a gratitude habit
Cultivating more gratitude is proven to boost your happiness and has multifold positive effects on your life. Here is a guide how to integrate a gratefulness routine into your daily life. I recommend putting three items on your bed pillow to remind you to be grateful for three things before going to sleep and putting them back on the pillow in the morning after getting up.
No-Poo Method (No Shampoo)
While many people wash their hair daily with shampoo, the over-washing removes the hair's natural conditioning and often causes an overproduction of grease. Therefore the idea of the "noo-poo" movement is to go back to the roots and to get the hair accustomed to its natural beauty. After an adjustment period participants claim to improve their hairs condition. More info here and here.
Try barefoot shoes
After a recommendation from a friend and reading again about barefoot shoes in a book I bought a pair and totally got into it. It takes an adjustment period though and you should really start slowly to give your feet enough time to adapt. However, I enjoy a much more natural feeling while running, feeling every stone and the features of the ground and because complex running shoes reduce your feet to primitive stumps, it is claimed that barefoot shoes are much healthier for your feet. I recommend Merells Vapor Glove or Vibram Fivefingers.
Cut out on something/Fasting
You might find that after an uncomfortable adjustment period, you need much less than you had thought. So why not try this out on something that you've always wanted to get rid off? For instance you could try coffee, meat, nicotine, alcohol, porn, sweets, facebook, fast food, tv or computer games. Begin with something like 2 weeks and extend if you like.
Language learning
If you hate learning languages and consider yourself plainly bad at languages the reason might just be that usual learning methods and lanugage classes suck. Get inspired by a TED speech from a guy that manages to become fluent in new languages in three month here (he also used to consider himself bad at languages). I tried his approach travlling Spain for two weeks and can confirm that it is much more effective than language classes - and also much more fun.
30 mini challenges for 30 days
Read more here.