I dont post about the site being down, as i feel like im hassling you guys to do something about it - which im not. However it still is down pretty frequently, as someone said usually from 10 - 11.30pm. But I havent had any problems for around a month until just a few days ago.
For me, sometimes i leave firefox open, sometimes i start a new session, but i always click my bookmark to go to portal.php and i get a page not found error, or page is taking too long to respond error.
Are there any system event logs on the server you can take a look at, the next time people say an outage occurrs? That will usually record incoming requests and report any error messages etc...
If you're struggling, it may be useful to post up the steps you've gone through so far to diagnise the problems and the changes you've made? Quite a few of us are/were developers and may have the skills to assist.
Keep up the good work guys.