Greek
The standard modern Greek keyboard layout
The key ";:" has the functionality of a dead key; you press it (nothing is printed) and then you press a vowel, and the vowel appears with a TONOS accent mark (άέήίύόώ). When you press ":" and then either IOTA (ι) or YPSILON (υ), these letters get the DIALYTIKA accent mark (ϊ ϋ). When pressing capital 'W' the result is TONOS with DIALYTIKA (ΐ ΰ).
` 1 2 3 4 5 6 7 8 9 0 - = ; ς ε ρ τ υ θ ι ο π [ ] \ α σ δ φ γ η ξ κ λ ´ ' ζ χ ψ ω β ν μ , . /
~ ! @ # $ % & * ( ) _ + : Σ Ε Ρ Τ Υ Θ Ι Ο Π { } | Α Σ Δ Φ Γ Η Ξ Κ Λ "" Ζ Χ Ψ Ω Β Ν Μ < > ?
There is a keyboard layout to type Classical Polytonic Greek. There is a bug report with this issue and GTK+ applications, described at GNOME Bugzilla #321896. See general instructions (in Greek) with screenshots from FC2.
All of classical Greek literature is available online and on CD-ROM from the Perseus Project at Tufts University, and the Thesaurus Linguae Graecae at University of California, Irvine.