1. Comment on a series of posts other professionals in your area of expertise seem to be talking about.
2. Read something in a totally different genre like philosophy or history and try and put it in the context of your job.
3. Blog some rhetorical questions that are on your mind.
4. Ask 4-5 smart people for a tip or best practice around something everyone in your area needs to know.
5. Take a look at your resume and write some first impressions/common misperceptions of yourself. How does this differ than what impression you wish people got and what steps or projects can you take on to bridge that gap?
6. Interview someone you find interesting by email. 3-5 questions will do.
7. Comment on two seemingly juxtaposed approaches to success in your area? Why does each work? Are they really mutually exclusive?
8. Write about someone or something that you appreciate.
9. Attend an event and write a thoughtful summary.
10. Share something that you do to make your work easier.
11. List your tools of the trade/most used apps and why you like them as well as a feature request for each.
12. Recruit a fictitious or All Star team to join you on a project or adventure and write about how they'd compliment you and each other.
13. Journal your attempt at creating a Top 25/50/100 list of the most interesting/innovative/disruptive/etc people in your space. Ask for recs, ruminate on criteria, etc. The second you say you're trying to do this you'll get lots of suggestions and you could turn around and interview all of those people, asking them for their suggestions for the list as well. You could get tons of posts out of the interviews if nothing else.
14. Writeup a theoretical exercise for a company changing something about the way they do business--like what if Twitter created a level of paid accounts or what if Facebook added features for the enterprise. Should Uber have shared rides? What kind of advertising mechanism should Tumblr have? Make sure you're respectful of the hard work the company has put in to get where they are going and keep in mind they've probably tought about your suggestion before.
15. Ruminate on what the future of something likes like 5, 10, 50 years from now. What would most people assume happens that they'll likely get wrong?
16. What industry lesson can we learn from a fictional book or movie?
17. Pick out a trendy area and write about how the current solutions may or may not be what ultimately wins in the space. Who has the best chance of solving that problem?
18. Observe some "average" people and how they do something related to your industry that others seem to miss. If you're an architect, how do most architects misunderstand people's home lives? What do doctors miss about typical patients, etc?
19. How are you "average" or not related to how the world is designed with you in mind? Where do you differ from the fat middle of the normal curve and how do you have to be conscious of this when doing your job?
20. If you were hiring someone for what you do and you could only select based on one character trait, what would it be and why?
21. If there was one industry conversation or negotiation that you would have liked to be a fly on the wall for, what would it be and how do you think it would have gone?
22. Promote a person or service for free--who or what has added awesomeness to your life that others need to know about.
23. What is the most simple, smallest task that you could do everyday for the next month that would improve your life and why?
24. What's the most annoying thing you have to do as part of your daily routine and how could technology fix it? Be as detailed on how the product would function as possible.
25. Take a company's approach and apply it to a new area. What would an auto mechanic look like if it was run by Southwest Airlines? If Apple built a car, what would it have? What if Teach for America placed Fortune 500 CEOs instead of teachers?