Is it possible to give 110%?

The short answer is yes, it is possible in some situations.  However, I don't know what situations you are referring to.  So, I will describe several different possible scenarios and show you how it works.

Scenario number one:  A bully asks you for 110% of your lunch money. 

This is possible.  For instance you have your lunch money, as well as other money, say money you were saving to buy your Wii.  You just give your lunch  money, as well as a 10% premium taken from your Wii money.  This is dangerous as next time the bully may ask for "all your money" leaving you pennyless, and Wiiless, just like me.  The best way for paying the extra 10% is to shake down other kids smaller than you.  In fact, if you play your cards right you could shake down enough to give up your lunch money, but still acquire enough other money to make ends meet.

Scenario number two:  Your boss asks you to give 110% effort.

This is technically impossible, but not for the reasons you think.  It is impossible thanks to statistics, and not the laws of nature.  You see, effort is a continuous variable.  A continuous variable is one for which, within the limits the variable ranges, any value is possible.  For example, 110.000001%, or 110.00005%, or any increasingly small percent.  Statistically the odds of achieving exactly 110% is impossible.  This is where the technicality comes in.  It all depends on the policy for significant digits at your place of employment.  For example, in cooking 1 cup of flour can have a margin of error.  Landing on Mars requires more precision (if this is your job however you may want to looking to possible lax policies for exchanging English and metric units). 

Scenario number three:  Your boss asks you to give more than 110%.

This is possible, and there are several approaches.  The first is the easiest.  This simply requires you to realign your baseline to 90.9% or lower, then when you perform at 100% it appears to be over 110%.  This approach works best for rare occasions and should be punctuated with signs of obvious fatigue, profuse sweating, panting, and possible sick days following completion.  The next approach is to simply work longer hours, start working 8.8 hour days, or skip lunch and breaks.  This is the least desirable option.  The third option is to get a clone.  You can alternate going into work so one can stay home and play games, or watch day time TV, or what ever.  Then when you are asked to "step up" you simply both "go to bat" and neither one of you needs to give over 60%.  The downside to this approach is the splitting of the pay check. 

So, lower your baseline and give me 90.9%.