I know many people who cache on their lunch hour and work downtown (or nearby). Here's a cache that won't tax your finding skills too much, but you will have to fulfill the challenge requirements:
You must have found 20 caches that ask a question in the cache title.
If there is a question mark on it, it is probably asking a question. Even if there is no question mark, that is OK, as long as it is a question.
Examples:
I voted! Did you? (GC40XJ6)
(How Much Is) That Doggie in the Window (GC1BG91)
Stop witch way? (GC3EF08)
Is It Morning Or Mourning? (GC2R6AM)
All cache types are acceptable. Finds are not limited by time or place.
Two ways you can demonstrate you have fulfilled the requirements are with a bookmark list (it must be public) or by listing the following info in your log: cache name, GC code, date found. For example, I would list one of caches above as:
Is It Morning Or Mourning?, GC2R6AM, 10/13/12
Or use another method that demonstrates you have fulfilled the qualifications.
Have fun and cache on.