According to scientific study how long are people comfortable surfing
while at work. Also, specifically, how long will people feel
comfortable playing an online game before feeling like they have to
get back to work (on average). Please cite your sources.

<Online usage at work.

TIME SPENT ON NON WORK-RELATED WEBSITES?of those that access non
work-related websites at work, men admitted to spending on average 2.3
hours per week on personal-related websites, and women admitted to
spending 1.5 hours per week.
Source: Websense
http://www.websense.com/global/en/PressRoom/PressReleases/PressReleaseDetail/index.php?Release=0605161213


This survey found that 19% of people spend under 30 minutes a day
playing games of the standard Microsoft package. 5% play for 30
minutes to 2 hours and 1% play for more than 2 hours.
For games additionally installed in the computer the results were
Under 30 minutes ? 16%
30 minutes to 2 hours ? 9%
More than 2 hours ? 2%

For online and network games. 
Under 30 minutes ? 9%
30 minutes to 2 hours ? 5%
More than 2 hours ? 2%

Source: Romir Monitoring.
http://www.rmh.ru/en/news/res_results/119.html

According to this survey, playing games at work has decreased with
only 6% of employees saying that they play computer games at work.
Source: Websense.
http://www.websense.com/global/en/PressRoom/PressReleases/PressReleaseDetail/?Release=050509928

Fourteen percent of employees admitted to playing online or downloaded
games at work. The average time spent doing so is 2.3 hours per week.
Men spend more time playing games -- 2.91 hours per week for men
versus 1.74 hours for women. >
Source: Websense.
http://www.wired.com/news/business/1,63240-0.html


<Search strategy:

<"surf at work" hours respondents>
<://www.google.com/search?hl=nl&rls=GGLG%2CGGLG%3A2006-26%2CGGLG%3Aen&q=%22surf+at+work%22+hours+respondents&lr=>

<"games at work" hours respondents>
<://www.google.com/search?hl=nl&rls=GGLG%2CGGLG%3A2006-26%2CGGLG%3Aen&q=%22games+at+work%22+hours+respondents&lr=>


<Hope this helps.>

http://ethics.csc.ncsu.edu/social/workplace/surfing/

http://www.braunconsulting.com/bcg/newsletters/summer2003/summer20034.html

http://abcnews.go.com/GMA/Careers/story?id=1519053

Some interesting reading... each site has some survey results and other fun facts.

My source is just myself, but this data suggests that the answer is in
the neighborhood of "a pretty long time". It depends somewhat on how
often my boss walks by, though, and whether he's recently asked me for
the results of a specific task I've been asked to perform.

If you're trying to find out whether a candidate game has the
capability to increase the level of comfort that people feel while
playing it at work, I would suggest you not rely on existing studies,
but rather do your own with the only variable being the game that your
volunteers are playing. This way, you can eliminate factors that might
skew the results of other studies relative to the results of a study
of your new, potentially world-beating game.