Istanbul: Day 2

Blue Mosque (free)
Hagia Sofia (20TL)
Yeni Marmara Cafe, blackberry tea
New Mosque (free)
Bab-i Hayat, lunch
Spice Market
Cezayir, dinner
Supperclub, drinks and dancing

The mosques were both beautiful but after just two, we were pretty mosque-ed out. There are many, many mosques in Istanbul so if you're into that, there are plenty more to see than just the two that we went to. However, Blue Mosque seems to be the most well-known so I'd say definitely visit that one and then venture from there.
Hagia Sofia was amazing. The mosaics were incredible and the structure itself is a sight to be seen. It's not free but even if you're on a tight budget, I'd say this one's worthwhile.
Spice Market is a definite must-see/do. It's beautiful, fun, and you can try free samples of Turkish Delights. The vendors do hassle you a bit to come and see their stalls but we just put on our cold, unyielding New Yorker faces and tore through without getting suckered in.
Supperclub was so-so. Turkish clubbing is quite different from what I'm used to; the drinks are fatally strong and no one actually dances. However, it was an experience and we had fun dancing nonetheless.
cats hanging out in front of the Blue Mosque

Blue Mosque courtyard
Blue Mosque
Blue Mosque, interior
Blue Mosque, singing priest man - chanted prayers the whole time, possibly all day long
Blue Mosque
Hagia Sofia
Hagia Sofia
Hagia Sofia

Hagia Sofia
Hagia Sofia mosaics

outside the Hagia Sofia

Arasta Bazaar
Yeni Marmara Cafe, with our blackberry tea (3TL)

Yeni Marmara Cafe, beautiful view overlooking the water
New Mosque courtyard
New Mosque, gorgeous tile
outside the New Mosque
Bab-i Hayat, lunch - meat pitta (left), yogurt kebab (right)
Spice Market

Spice Market, cheese, fish, meat
Galata Bridge

cats at Cezayir
Supperclub, Bosphorus Bridge