Python 2.4.4 console for SymPy 0.5.6-hg. These commands were executed:
>>> from __future__ import division
>>> from sympy import *
>>> x, y, z = symbols('xyz')
>>> k, m, n = symbols('kmn', integer=True)
>>> Basic.set_repr_level(2) # 2D output
>>> pprint_try_use_unicode() # try to setup unicode pprint
In : sqrt((sqrt(x+1))+1)
╲╱ 1 + ╲╱ 1 + x
In : th, ph = Symbol("theta"), Symbol("phi")
In : Integral(sin(th)/cos(ph), (th,0,pi), (ph, 0, 2*pi))
⎮ ⎮ sin(θ)
⎮ ⎮ ────── dθ dφ
⎮ ⎮ cos(φ)
More examples can be found on the wiki page PrettyPrinting.
Fredrik also played with the idea of ascii plotting. I am a huge fan of a terminal, because this is very versatile - I can use it over ssh, I can copy & paste, save the results to a file etc. I can easily script it. And the most important - I just prefer to write my programs in vim and execute them as a simple script. Any GUI, even the best one (or in the browser), is not giving me such a power. So I like the idea of making the terminal experience as pleasant as possible.