Aside from the hard time reaching the deadline, finding way how to avoid being late or be shouted at by the boss, one of the many problems of people working in a secluded office is how to fight sleepiness. I wouldn't believe if you will tell me you haven't slept in front of your computer, laid your head on the office table or closed your eyes to sleepiness while in a meeting. Well, don't be ashame, it's as normal as how you breath air. You cannot expect even the best employee to stay awake all the time while just waiting for calls or for e-mails. I believe it's in our body system that makes us feel sleepy at times that we do not engage ourselves lively with our surrounding. If your office has a strict rule of "Please be quiet!", gah!, I am pretty much sure the silent wind will make you yawn.
Based on personal experience, I feel sleepy after every lunch. I don't know why, but everytime I have filled my stomach with something, I will give a very deep yawn and eventually, my eyes will close and I'm off to wonderland. Well, it's different if your working in an office. I guess if I also work in an office, I will not be that sleepyhead because the thought of having your boss caught you while dreaming is such a nightmare, and I would try to avoid that seriously.
Anyway, what I usually do when I'm sleepy but cannot afford to sleep, specially if there are exams and important things to do is I get my Disc-Man (lately I upgraded it to an iPod) and find songs that sounds very lively. I sometimes challenge myself to listen to songs that will annoy me haha. I don't like heavy metal songs or those music that is very loud. I don't really know if they are singing or just shouting. I hate those songs, but for the sake of waking my self up, I dare to listen to it.
Of course you have to use an earphone so you can hear the wholeness of the sound so there's no space for sleeping and also to avoid disturbing others. But the best reason why you should use an earphone is that you don't want to be heard by your boss. That's a disaster! I'm not a coffee drinker so that's the best I can advise you to do if ever you feel sleepy during your office hours. One more thing, try to look around and work your eyes with your surrounding, don't get caught by your boss with your earphones plugged to your ears. I'm sure you will not like what happens next. Heh!