One of My Favourite Hadiths:

Anas (radhiallahu anhu) said that he heard the Messenger of Allah (sallallahu alaihi wa-sallam) say: “Allah the Exalted said: “O son of Adam! As long as you invoke Me and plead to Me, I will forgive you whatever you have committed, and I will not make much of it. O son of Adam! If your evil deeds reach the borders of the sky, and then you ask Me for forgiveness, I will forgive you. O son of Adam! If you bring forth the earth full of errors, then you meet Me while you do not associate anything (or anyone) with Me, I will bring forth for you its full forgiveness.” [At-Tirmidhee (Shaikh Albanee rendered it as Hasan)]

The Major Sins

1. Associating Anything with Allah (SWT)
2. Murder
3. Practising Magic
4. Not Praying
5. Not Paying Zakat
6. Not fasting on a Day of Ramadan without excuse
7. Not performing Hajj, while being able to do so
8. Disrespect to Parents
9. Abandoning Relatives
10. Fornication and Adultery
11. Homosexuality
12. Interest
13. Wrongfully consuming the Property of an Orphan
14. Lying About Allah (SWT) and his Messenger (SAW)
15. Running away from the battlefield
16. A leader's deceiving their people and being unjust to them
17. Pride and arrogance
18. Bearing false witness
19. Drinking alcohol
20. Gambling
21. Slandering Chaste Women
22. Stealing from the spoils of war
23. Stealing
24. Highway robbery
25. Taking false oath
26. Oppression
27. Illegal gain
28. consuming wealth acquired unlawfully
29. committing suicide
30. frequent lying
31. judging unjustly
32. giving and accepting bribes
33. imitating the opposite gender
34. being cuckold
35. marrying a divorced woman in order to make her lawful for the first husband
36. not protecting oneself from urine
37. showing off
38. learning knowledge of the religion for the sake of this world and concealing that knowledge
39. betrayal of trust
40. recounting favors
41. denying Allah (SWT)'s decree
42. eavesdropping
43. carrying tales
44. cursing
45. breaking contracts
46. believing in fortune tellers and astrologers
47. a woman's bad conduct towards her husband
48. making statues and pictures
49. lamenting, wailing, tearing clothing and such when an affliction befalls you
50. treating others unjustly
51. overbearing conduct toward the wife, the servant, the weak, and animals
52. offending one's neighbour
53. offending and abusing Muslims
54. offending people and having an arrogant attitude toward them
55. trailing one's garment in pride
56. men's wearing of silk and gold
57. a slave's running away from his master
58. slaughtering an animal in the name of someone or something other than Allah (SWT)
59. to knowingly claim someone who isn't your father, as your father. 
60. arguing and disputing violently
61. hoarding water
62. giving short weight or measure
63. feeling secure from Allah (SWT)'s plan
64. offending Allah (SWT)'s righteous friends
65. not praying in congregation without an excuse
66. persistently missing friday prayers without an excuse
67. usuping the rights of the heir through bequests
68. deceiving and plotting evil
69. spying for the enemy of the Muslims
70. cursing or insulting any of the Companions of Allah (SWT)'s Messenger

Saturday

Saturday's Super Prayer:

4 rakaa's 

Recite in each rakaa:

• Al Fatiha
• Al Ikhlas 3 times
• Ayatul Kursi

God will write for you the reward of one Hajj, one Umra, one year's worth of fasting, and one years worth of prayer FOR EACH WORD, and you will reside with the Prophets and martyrs under the Throne of God.

So you can see just how intense some of these prayers can be! Ikhlas 100 times!? How do you even count that!? You'd need someone keeping track, or some kind of voice activated counter or something! Some aren't so bad though, like that last one. I tip my hat to anyone who can do Thursday's though. If you can do that, you deserve a medal or something! :)

Friday

Friday's Super Prayer:

After the sun rises up to one bow's distance or more, make full ablution

2 rakaas, with faith, hoping for good reward

God will write for you 200 hundred rewards, and remove 200 sins.

4 rakaas 

God will open for you in Paradise 800 doors and forgive all your sins.

12 rakaas

1200 merits will be written, 1200 sins will be erased, and 1200 doors will be opened for you in Paradise.

4 rakaa's, in the Masjid after Jumaa prayer, 

Recite in each rakaa:

• Al Fatiha 50 times
• Al Ikhlas 50 times

You will not die until you see your place in Paradise, or your place in Paradise is shown to you.

Thursday

Thursday's Super Prayer:

2 rakaa's between Dhur and Asr prayers.

Recite in THE FIRST rakaa

• Al Fatiha
• Ayatul Kursi 

Again, I can't tell but it says: "Al Fatiha and Ayatul Kursi in the first rakat one hundred times"

Recite in THE SECOND rakaa

• Al Fatiha
• Al Ikhlas

Again: "Al fatiha and Ikhlas in the second rakat one hundred times"

Followed by:

•  Darud 100 times.

God will reward you with fasting of Rajab, Shaban and Ramadan, the rewards of one Hajj and innumerable virtues will be written for you.