As I am working in Menlo park during this summer, I had to find a new place to go to Friday Jummah (congregational) prayers. Menlo park itself does not have a mosque and there are hardly any Muslims around the area. Fortunately, I found two options which worked out for me. I take 2 - 3 hours off every Friday to make it to the prayers. It's good to get away from the busy life for at least a few hours and be with the community every week.
Islamic Society of Stanford University holds a Friday prayer starting at 12.15 pm (till 1.10 pm). This one is the closest to Menlo park (about 2 miles away). It is managed by the students at Stanford. Stanford does not have a mosque though. (Good thing about Purdue, where I study, is that it has a mosque in the campus itself and there is a large Muslim crowd.) They hold the Friday prayers in the 3rd floor of the old Union building (However, they do have special wudu areas). You get about 50-60 people altogether. Where to park your car? There is a paid parking lot at the intersection of Mayfield avenue and Lagunita drive. You can either use your credit card or use coins to pay. During May/June (where the Spring semester was still in progress), it was somewhat difficult to find a parking spot in that car park (You better go there about 1/2 an hour early). But now, being the summer, there is ample parking available in that lot.
Muslim Community Association (MCA) mosque in Santa Clara (Yelp). It's about 15 miles (1/2 an drive) from Menlo park, but I very much like this place - it's a quite big mosque with a large gathering. If I have more time, I usually drive to this place instead of Stanford. They have two Jummah prayers one at 12.15 pm (I usually go to this one) and the other at 1.30 pm. In addition to the large prayer areas, the mosque has many other specialized rooms. Talking about parking, it does have a big parking lot, but it gets filled pretty quickly on Fridays - so you better go there a few minutes before if you want to park in the mosque itself. There is also a parking lot close to the mosque which you can use.
Other useful links:
South Bay Islamic Association
Muslim Community Association
Hope this information might be useful to those who are new to this area.