#1. Thank the under appreciated. Nothing tells people that they are appreciated like a free lunch. Those who deliver packages, messages, perform surveys, clean the copy machine, fix the copy machine, and so forth- deserve some recognition. If you suddenly surprise them with a catered lunch, even from a sub shop, they will know that they count and the other staff will become motivated- as well as taking notice of them, too.
#2. Ask everyone what they want to do but are waiting on? Yes you the boss can change things. If you have a clerk in the office waiting on a delivery man to pick up a package so she can produce, run out and pick it up for her. It will not hurt you to show your staff that you are capable of doing their jobs.... BTW- they often think upper management can't. If you can show your staff, on a gloomy day, that you can get your hands dirty- they will become motivated. Trust me on this!
#3. Hire a corporate fitness company for the day. If it is slow consider group stretching. It is great for the creative juices. Corporate fitness companies can be a little pricey but you can get them in the office the same day. Or, just take the team outside and do a half an hour of stretching. Fresh air is always good for the soul and productivity.
As people we tend to get stuck sometimes. We can all have off days in life and business. When the entire office is having an off day, it is up to you- the business owner- to re-inspire and motivate! I hope these tips have been helpful. I am looking forward to hearing your suggestions as to what has worked for your company in the past and present!